Adding "Popping" as reference in "Resources"

Also sorting the list alphabetically
Merge pull request #96 from hfossli/patch-1

Adding "Popping" as reference in "Resources"
Use Travis CI's default xctool support

Details @ http://docs.travis-ci.com/user/languages/objective-c/.
Merge pull request #98 from LegNeato/master

Use Travis CI's default xctool support
Cancelling any ongoing animation in UIScrollView

If there is any UIScrollView animation of any sort:
- Say the user scrolled a little bit and the UIScrollView is decelerating. 
- Or `[scrollView setContentOffSet:p animated:YES]` was triggered.
- Or the user tapped on the statusbar to scroll to top

These animations will interfere with pop-animation since they will both work simultaneously. Setting `-[UIScrollView setContentOffset:animated:]` will cancel/stop any UIScrollView animation.
Fixed warning: 'const' type qualifier on return type has no effect [-Wignored-qualifiers]
Fixed fields initialization order warnings [-Wreorder]
Fixed warning: comparison of integers of different signs [-Wsign-compare]
Fixed warning: auto property synthesis is synthesizing property not explicitly synthesized [-Wobjc-missing-property-synthesis]
Fixed warning: weak instance variable '_delegate' is accessed multiple times in this method but may be unpredictably set to nil; assign to a strong variable to keep the object alive [-Warc-repeated-use-of-weak]
Added more compilation warnings.
Fixed auto property synthesis for POP tests.
Removed unused header.
Fixed more warning: comparison of integers of different signs.
Added missing methods definition.
Fixed CGFloat to double conversion when interpolating basic animations.
Fixed typo.
Merge pull request #100 from hfossli/patch-1

Cancelling any ongoing UIScrollView animation
Merge pull request #102 from jcbertin/master

Fixed miscellaneous warnings.
Fixed typo in `#if !TARGET_OS_**I**PHONE`