CI server build and release for brewpi spark code

[m-mcgowan]

Since we plan to release at least every 2 weeks, and automated release process will ease the burden of doing that plus ensure consistency.

At a minimum the release build should:

• pull the latest state from the master branch
• fetch the version information from the working copy
• tag the repo with the version number (if necessary, force pushing the tag)
• perform a clean build of the controller app
• rename the artefact to include the version number - brewpi-1.2.3.bin
• push the artefact to the github releases page