Added Execute with no CancelToken to IStage and added impl to CancellableStage
Extracted ICancelToken interface from CancelToken and updated Pipline and Stage impls to use interface vs concrete type
added support for Pipeline using an external ICancelToken impl vs one created during the call
Merge branch 'master' of github.com:asipe/SupaCharge
udpated to 1.0.0.22