Implement CMP presigning

[adr1anh]

• include all protocols in README.md, write a bit about broadcast, make comments.
• Revamp handler to take into account broadcast.
• added the internal/test package with several testing related methods.
  • testing rounds is run in parallel, and allows for extra malicious behavior
  • integration test for handler
  • generate fake CMP configurations
• hash:
  • Validate checks whether the commitment or decommitment is 0
  • Use reflection to handle encoding.BinaryMarshaller objects in HashAny.
• MtA:
  • Remove extraneous structure, in favor of a better description of affg/affp proofs.
• round:
  • remove protocol ID type in favor of a string
  • Helper returns an Info struct for the handler.
  • move message.Content to round, and use separate round message type to allow for better round embedding.
  • Added Broadcast round which handles Lindell's echo broadcast.
  • Change round interface to use new message type.
  • change Round->Session which includes the session information.
  • include pool.Pool in the Helper, as well as the threshold.
• protocol:
  • create top level package for protocol -> better UX
  • implement optional session ID
  • rework pool argument to be last