DOCSP-4379 Validate and clarify intro in README (#173)

* DOCSP-4379 Validate and clarify intro in README

- Ran through the steps in README to validate their current accuracy
- Some improvements/clarifications made

* Addressing comments

README.md

@@ -20,7 +20,7 @@ The official [MongoDB Stitch](https://stitch.mongodb.com/) SDK for iOS/Swift.
 
 ## Installation
 
-### XCode/iOS
+### Xcode/iOS
 
 #### CocoaPods
 
@@ -30,7 +30,7 @@ The official [MongoDB Stitch](https://stitch.mongodb.com/) SDK for iOS/Swift.
 $ gem install cocoapods
 ```
 
-> CocoaPods 1.6.0+ is required to build the Stitch iOS SDK 5.0+.
+- Note: CocoaPods 1.6.0+ is required to build the Stitch iOS SDK 5.0+.
 
 To integrate the iOS SDK into your Xcode project using CocoaPods, specify it in your `Podfile`:
 
@@ -69,25 +69,33 @@ Open the `.xcworkspace` file generated by `pod install` to access your project w
 #### Set up an application on Stitch
 1. Go to [https://stitch.mongodb.com/](https://stitch.mongodb.com/) and log in to MongoDB Atlas.
 2. Create a new app in your project with your desired name.
-3. Go to your app in Stitch via Atlas by clicking Stitch Apps in the left side pane and clicking your app.
-3. Copy your app's client app id by going to Clients on the left side pane and clicking copy on the App ID section.
-4. Go to Providers from Users in the left side pane and edit and enable "Allow users to log in anonymously".
+3. Go to your app in Stitch via Atlas by clicking 'Stitch' in the left side pane and clicking your app.
+3. Copy your Stitch App ID from the top of the left side pane.
+4. Enable anonymous authentication by going to the Users page in the left side pane, selecting the Providers tab, and enabling the "Allow users to log in anonymously" option.
 
-#### Set up a project in XCode/CocoaPods using Stitch
+#### Set up a project in Xcode/CocoaPods using Stitch
+
+1. Download and install [Xcode](https://developer.apple.com/xcode/). 
+
+- Note: Xcode 10.1 (10B61) is currently the maximum supported version. To install an old version of Xcode, see [https://developer.apple.com/download/more/](https://developer.apple.com/download/more/).
 
-1. Download and install [XCode](https://developer.apple.com/xcode/)
 2. Create a new app project with your desired name. Ensure that Swift is the selected language.
+
+- Note: iOS 11.0 is the minimum iOS Deployment Target.
+
 3. Navigate to the directory of the project in a command line, and run `pod init`.
 4. In the `Podfile` that is generated, add the following line under the dependencies for your app target:
 
 ```ruby
     pod 'StitchSDK', '= 5.1.0'
 ```
 
-5. Run `pod install`
-6. Open the generated `.xcworkspace` file
-7. Your app project will have all the necessary dependencies configured to communicate with MongoDB Stitch.
-8. To use basic Stitch features, `import StitchCore` in a source file.
+See above for the list of optional Stitch service pods that you may add to your Podfile.
+
+5. Run `pod install`.
+6. Open the generated `.xcworkspace` file. Your app project will have all the necessary dependencies configured to communicate with MongoDB Stitch.
+7. To use basic Stitch features, `import StitchCore` in a source file.
+8. To create BSON documents and BSON values like ObjectId, `import MongoSwift` in a source file.
 9. To access a remote MongoDB instance via Stitch, `import StitchRemoteMongoDBService` in a source file.
 
 #### Using the SDK
@@ -99,17 +107,20 @@ Open the `.xcworkspace` file generated by `pod install` to access your project w
     // at the top of the file
     import StitchCore
 
+    // ...
+
     // in `application(_:didFinishLaunchWithOptions)`
     do {
         _ = try Stitch.initializeDefaultAppClient(
             withClientAppID: "your-client-app-id"
         )
+        print("Successfully initialized default Stitch app client!");
     } catch {
-        print("Failed to initialize MongoDB Stitch iOS SDK: \(error)")
         // note: This initialization will only fail if an incomplete configuration is 
         // passed to a client initialization method, or if a client for a particular 
         // app ID is initialized multiple times. See the documentation of the "Stitch" 
         // class for more details.
+        print("Failed to initialize MongoDB Stitch iOS SDK: \(error)")
     }
 ```
 
@@ -121,26 +132,26 @@ Open the `.xcworkspace` file generated by `pod install` to access your project w
 ```
 
 ##### Logging In
-1. We enabled anonymous log in, so let's log in with it; add the following anywhere in your code:
+1. We enabled anonymous log in, so let's log in with it! Add the following anywhere in your code:
 
 ```swift
 let client = Stitch.defaultAppClient!
 
 print("logging in anonymously")
 client.auth.login(withCredential: AnonymousCredential()) { result in
-        switch result {
-        case .success(let user):
-            print("logged in anonymous as user \(user.id)")
-            DispatchQueue.main.async {
-                // update UI accordingly
-            }
-        case .failure(let error):
-            print("Failed to log in: \(error)")
-        }
-    }
+      switch result {
+      case .success(let user):
+          print("logged in anonymous as user \(user.id)")
+          DispatchQueue.main.async {
+              // update UI accordingly
+          }
+      case .failure(let error):
+          print("Failed to log in: \(error)")
+      }
+  }
 ```
 
-2. Now run your app in XCode by going to product, Run (or hitting ⌘R).
+2. Now run your app in Xcode by going to product, Run (or hitting ⌘R).
 3. Once the app is running, open up the Debug Area by going to View, Debug Area, Show Debug Area.
 4. You should see log messages like:
 
@@ -151,7 +162,7 @@ logged in anonymously as user 58c5d6ebb9ede022a3d75050
 
 ##### Executing a Function
 
-1. Once logged in, executing a function happens via the StitchClient's `callFunction()` method
+1. Once logged in, you can execute a [Stitch Function](http://docs.mongodb.com/stitch/functions) with the StitchClient's `callFunction()` method:
 
 ```swift
     client.callFunction(
@@ -166,15 +177,24 @@ logged in anonymously as user 58c5d6ebb9ede022a3d75050
     }
 ```
 
-2. If you've configured your Stitch application to have a function named "echoArg" that returns its argument, you should see a message like:
+2. If you've configured your Stitch application to have a function named "echoArg" that returns its argument, i.e.:
+
+```javascript
+// Stitch Function called 'echoArg'
+exports = function(arg) {
+  return arg;
+};
+```
+
+Then you should see a message in the Xcode Debug Area like:
 
 ```
 String result: Hello world!
 ```
 
 ##### Getting a StitchAppClient without Stitch.defaultAppClient
 
-In the case that you don't want a single default initialized StitchAppClient, you can use the following with as many client app IDs as you'd like to initialize clients for a multiple app IDs:
+In the case that you don't want a single default initialized StitchAppClient, you can use the following with as many client app IDs as you'd like to initialize clients for multiple app IDs:
 
 ```swift
     do {