Containerization and minor fixes

[balazsprehoda]

This pull request includes:

• Pre-compiled fabricbeat agent for (built on Ubuntu 18.04 LTS)
• Dockerfile to build fabricbeat image. ( resolves #32 )
• Example for demonstration of fabricbeat image usage.
• Documentation updates to include Docker option in prerequisites and setups.
• Binding node chaincode version to 1.4.0 in dummycc to enable variable parameter count. ( resolves #36 )
• Usage of fabric/protoutil Go package for hash generation.

I also published a Docker image for fabricbeat on Dockerhub: https://hub.docker.com/r/balazsprehoda/fabricbeat

By using pre-compiled or Docker version of the agent, the project can be independent from Go, Python and virtualenv and all the inconvenience coming with them. I hope this makes the project more user-friendly.