v0.6: Structured API, Console Mode, and no more counting

• Provides a much more structured API with different layers. New APIs can be implemented by introducing a codec to decode commands and encode responses. Everything is structured in modules and the API is extensible (e.g. with more deployment commands).
• Offers a console mode (Closes #3 - See also #5 ). This uses the composer API and maintains a state of stored and intermediate processes. Simplified commands and improvements in the selection arguments of the actions are provided. An automated script to export JSON responses from a console script is provided.
• Allows more control over channel names (Closes #1 - See also #4 ). Proofs are now dependent on a custom string label and have their own counter starting from 0.
• Updates Scala code generation to PEW 1.3.0 (Closes #6)
• Moves provenance to the process structure (Closes #7)
• Cleans up Actionstate and adds a merged field for WITH_TAC.
• Improves WITH_TAC in a few ways. It now reports all inputs that are merged in the composition. It also reduces the amount of search we were doing. The code is cleaner and commented now.
• Improves filtering of used inputs in JOIN_TAC, by using filter_once and caring about cardinality. This improves handling of reused channels (Closes #9).
• Adds some documentation in org-mode format, with more to come.