C.D. machinery - simplified the retrieval of bintray github API

There is no point using a project property API, env. variables for local testing and development work just fine (we have to use env vars anyhow as Travis uses them).
C.D. machinery - exposed a method for incrementing versions

This way, we can increment versions without invoking the task. This is useful for building a release procedure.
C.D. machinery - reworked the release steps

Enhancement #95

1. Changed the user to be an artificial 'Continuous Delivery Drone' instead of myself.
2. Added some basic dry-running capabilities (needs more work and tidy-up).
3. Changed the procedure so that there is only one git push at the end.
C.D. machinery - avoided shallow fetch of gh-pages

This way I can test out the machinery on a forked mockito. Without this change, I'm getting "fatal: git fetch-pack: expected shallow list" error.
C.D. machinery - started documenting the plan for the release automation
Improved the documentation a little bit.
JUnit @Rule implementation added

Fixes #85
Moved the new MockitoJUnitRule to 'junit' package.