Add unit test for web page without JavaScript player URL
Refactor webpage parsing
Add test for protected videos with JavaScript functions in var scope

YouTube recently changed the JavaScript player code and JavaScriptCore now fails to properly evaluate it
Have dummy `window` and `document` objects

JavaScript evaluation fails early without `window` and `document` objects. Dummy objects are provided in order for the signature function to be properly evaluated.

Fixes #52
Update README with up-to-date linker flags
Add unit test for broken signature function

Skip URLs when signature unscrambling fails in order to get proper restricted playback error (XCDYouTubeErrorRestrictedPlayback) instead of media player playback error caused by an invalid stream URL (missing signature).
Upgrade to Xcode 6 recommended settings
Add default "XCDYouTubeKit iOS Framework" target

Also rename "XCDYouTubeKit iOS" into "XCDYouTubeKit iOS Static Library"
Cleanup versions settings

Use settings defined at the project level instead, they are shared between the iOS and OS X frameworks targets.
Cleanup "Deployment" settings
Cleanup "Linking" settings
Cleanup "Apple LLVM 6.0 - Code Generation" settings
Cleanup "Apple LLVM 6.0 - Preprocessing" settings
Cleanup warnings settings
Cleanup "Apple LLVM 6.0 - Language - C++" settings
Fill "Compile Sources", "Link Binary With Libraries" and "Headers" build phases
Disable auto import warning to fix iOS framework compilation
Use the iOS framework instead of the static library in the demo app
Update `XCDYouTubeKit iOS Static Library` scheme name for Travis
Delete duplicate XCDYouTubeKit group entry