Converting all images to relative references to make HTTPS happy

_episodes/02-filedir.md

@@ -139,7 +139,7 @@ which will be constructed in a similar way, but not be exactly identical.
 
 On Nelle's computer, the filesystem looks like this: 
 
-![The File System]({{ site.github.url }}/fig/filesystem.svg)
+![The File System](../fig/filesystem.svg)
 
 At the top is the **root directory**
 that holds everything else.
@@ -171,7 +171,7 @@ Underneath `/Users`,
 we find one directory for each user with an account on Nelle's machine, 
 her colleagues the Mummy and Wolfman.  
 
-![Home Directories]({{ site.github.url }}/fig/home-directories.svg)
+![Home Directories](../fig/home-directories.svg)
 
 The Mummy's files are stored in `/Users/imhotep`,
 Wolfman's in `/Users/larry`,
@@ -780,7 +780,7 @@ and we will see it in many other tools as we go on.
 > 3.  `2012-12-01/ 2013-01-08/ 2013-01-27/`
 > 4.  `original pnas_final pnas_sub`
 >
-> ![File System for Challenge Questions]({{ site.github.url }}/fig/filesystem-challenge.svg)
+> ![File System for Challenge Questions](../fig/filesystem-challenge.svg)
 >
 > > ## Solution
 > > 1. No: there *is* a directory `backup` in `/Users`.

_episodes/03-create.md

@@ -147,7 +147,7 @@ holding it down, press the O key) to write our data to disk
 (we'll be asked what file we want to save this to:
 press Return to accept the suggested default of `draft.txt`).
 
-![Nano in action]({{ site.github.url }}/fig/nano-screenshot.png)
+![Nano in Action](../fig/nano-screenshot.png)
 
 Once our file is saved, we can use `Ctrl-X` to quit the editor and 
 return to the shell.

_episodes/04-pipefilter.md

@@ -341,7 +341,7 @@ we get three processes with data flowing from the files,
 through `wc` to `sort`,
 and from `sort` through `head` to the screen.
 
-![Redirects and Pipes]({{ site.github.url }}/fig/redirects-and-pipes.png)
+![Redirects and Pipes](../fig/redirects-and-pipes.png)
 
 This simple idea is why Unix has been so successful.
 Instead of creating enormous programs that try to do many different things,

_episodes/05-loop.md

@@ -239,7 +239,7 @@ done
 ~~~
 {: .bash}
 
-![For loop in action]({{ site.github.url }}/fig/shell_script_for_loop_flow_chart.svg)
+![For Loop in Action](../fig/shell_script_for_loop_flow_chart.svg)
 
 This loop runs the `cp` command once for each filename.
 The first time,

_episodes/07-find.md

@@ -257,7 +257,7 @@ Again,
 it has a lot of options;
 to show how the simplest ones work, we'll use the directory tree shown below.
 
-![File Tree for Find Example]({{ site.github.url }}/fig/find-file-tree.svg)
+![File Tree for Find Example](../fig/find-file-tree.svg)
 
 Nelle's `writing` directory contains one file called `haiku.txt` and four subdirectories:
 `thesis` (which contains a sadly empty file, `empty-draft.md`),

_includes/all_figures.html

@@ -1,13 +1,13 @@
-<p><img alt="The File System" src="{{ site.github.url }}/fig/filesystem.svg" /></p>
+<p><img alt="The File System" src="../fig/filesystem.svg" /></p>
 <hr/>
-<p><img alt="Home Directories" src="{{ site.github.url }}/fig/home-directories.svg" /></p>
+<p><img alt="Home Directories" src="../fig/home-directories.svg" /></p>
 <hr/>
-<p><img alt="File System for Challenge Questions" src="{{ site.github.url }}/fig/filesystem-challenge.svg" /></p>
+<p><img alt="File System for Challenge Questions" src="../fig/filesystem-challenge.svg" /></p>
 <hr/>
-<p><img alt="Nano in action" src="{{ site.github.url }}/fig/nano-screenshot.png" /></p>
+<p><img alt="Nano in Action" src="../fig/nano-screenshot.png" /></p>
 <hr/>
-<p><img alt="Redirects and Pipes" src="{{ site.github.url }}/fig/redirects-and-pipes.png" /></p>
+<p><img alt="Redirects and Pipes" src="../fig/redirects-and-pipes.png" /></p>
 <hr/>
-<p><img alt="For loop in action" src="{{ site.github.url }}/fig/shell_script_for_loop_flow_chart.svg" /></p>
+<p><img alt="For Loop in Action" src="../fig/shell_script_for_loop_flow_chart.svg" /></p>
 <hr/>
-<p><img alt="File Tree for Find Example" src="{{ site.github.url }}/fig/find-file-tree.svg" /></p>
+<p><img alt="File Tree for Find Example" src="../fig/find-file-tree.svg" /></p>