update project settings
Expose NSData-using interface for creating UIImage instances
version bump
change source URL
refactor for more concise interface
more refactoring

rely on naming conventions for constructors, use NSParamenterAssert
README update
bump version to reflect API incompatibility
bump version to reflect API incompatibility (2)
Picked changes from https://github.com/escherba/iOS-WebP
Picked changes from https://github.com/escherba/iOS-WebP
Remove surplus NSAsserts from merge