IMPL: ChangeSignature processor
- add: ChangeSignature processor, trait, testcase, and test resources
FEATURE: enable to put generated factory method to arbitray classes
- add: IntroduceFactoryTest2 for testing arbitray location of generated factory method
- modify: RSTIntroduceFactory for dealing with API for specifying location of factory method
- reject: specifying access modifier of factory method (not works)
Merge branch 'IMPL_change-signature'