- finish spec fmt image writer and raw bitmap writer.
- fix a possible fatal issue in ReadBuffer(). return nullptr simply rather than allocate a blank buf. otherwise the process of use nullptr to check result will be broken.
- add CanSaveAlpha() method in CKBitmapHandler.
- remove VTImage.hpp to make sure stb image do not need external project to ref.
- finish CKStateChunk write part. add some compatibilty code.
- add debugger pause function
- add filename getter for CKPathManager.