Remove ReactiveCocoa from SampleCustomControls:
* Removed ‘RACEXTScope.h’
* Replace ‘@stringify()’ and ‘@weakify()’ by ‘typeof(self) __weak weakSelf’ and ‘typeof(self) strongSelf’
Updated ControlsViewController.xib to fix UI frame warning.
Updated initialization method:
* Removed ‘- init;’ since ‘- initWithNibName:bundle:’ is designated initializer.
* Added ‘- initWithCoder:’ for UIViewController is unarchived from storyboard.

Updated configureConstraintsForControlsView:
* using visualFormat to configure controlsView's layout constraints.
Merge pull request #1 from ychang/YW.Modern.UI

YW Modern UI