@Contracted not processed correctly

[barneyb]

Trying to work around #48 I removed my @Contracted annotation, but all the contracts were still morphed into the generated code, and even more interestingly, the emitted bytecode had @Contracted added back onto the class.

The docs seem to imply that without that annotation, not GContracts AST transforms will be done, but that doesn't actually seem to be the case.