Added BasicDecorators#before and #after

--HG--
extra : amend_source : 86d9b595bd3fe0b3dca18e4c01ffb9a426380ce8
Correctly namespace the InvalidRBC exception
Remove redundant module declaration

--HG--
extra : amend_source : 74ecaa556c4bd0b00ac8f5b3e05af8d173952592