Update Travis configuration for Xcode 8 (#3)

.travis.yml

@@ -1,13 +1,12 @@
 language: objective-c
-osx_image: xcode7.2
+osx_image: xcode8
+env:
+  - DESTINATION="OS=10.0,name=iPhone 6s" SCHEME="Example" SDK=iphonesimulator10.0
 
 before_install:
-- brew update
-- brew outdated carthage || brew upgrade carthage
-- if brew outdated | grep -qx xctool; then brew upgrade xctool; fi
 - pod install --project-directory=TokenRow/Example
 - gem install xcpretty --no-rdoc --no-ri --no-document --quiet
 
 script:
-- xctool clean build -workspace TokenRow/Example/Example.xcworkspace -scheme Example -sdk iphonesimulator
-- set -o pipefail && xcodebuild test -workspace TokenRow/Example/Example.xcworkspace -scheme Example -sdk iphonesimulator9.3 ONLY_ACTIVE_ARCH=NO | xcpretty
+- xcodebuild clean build -workspace TokenRow/Example/Example.xcworkspace -scheme "$SCHEME" -sdk "$SDK"
+- xcodebuild test -workspace TokenRow/Example/Example.xcworkspace -scheme "$SCHEME" -sdk "$SDK" -destination "$DESTINATION" | xcpretty -c