auto-update project in Xcode 5
separate library classes from demo
rename library to match convention
Xcode 5 user data git ignore
cocoa pod ready, arc support
Merge remote-tracking branch 'nlap/master'

* nlap/master:
  cocoa pod ready, arc support
  Xcode 5 user data git ignore
  rename library to match convention
  separate library classes from demo
  auto-update project in Xcode 5

Conflicts:
	Classes/YRKSpinningProgressIndicator.m
	Code/YRKSpinningProgressIndicator.h
Small cleanup

* Update README and change extension to .md
* Remove and ignore .xccheckout
* Change URLs in the podspec
* Let Xcode do some project validation
Update build settings

* Move things to the xcconfig file, and remove from Xcode GUI.
* Remove Prefix.pch (use modules).
* Let Xcode update the xib.
* Can’t do 32-bit with ARC.
Clean up code/style

* Use properties where possible.
* Don’t need to @synthesize, declare ivars, or pre-declare private methods.
* Use shared method for calculating the alpha for current state, rather
  than relying on the previous frame of animation.
* Change fade-out to time-based.