Updated to latest version of library.
Preparation for 3.1 release.
Added release date to change log.
Handle invocation arguments of type Class.
Merge pull request #140 from patrickhartling/invocation_with_class_objects

Handle invocation arguments of type Class
Updated project files in order to fix build errors (added link to UIKit and CoreGraphics frameworks). Fixed unit tests fail - XCTAssertEqual validates the arguments types. Added explicit type cast.
Removing CoreGraphics dependency introduced by a pull request.
Preparation for 3.1.1 release.