Removed support for Xcode 4. No longer building with garbage collection support enabled.
Improved compatibility for future Xcode versions.
Updated readme.
Removing old Xcode 4-specific method.
Check for a method declaration instead of just matching the method name. This ensures that variables named imageNamed/spriteWithFile/etc don't incorrectly receive the imageNamed autocomplete results.
The methodName entries in Completions.plist are now unused, since this is the only place it was being used.
Fixes #34.