readme - branches, contribution, clarifications

[anEXPer]

Primarily adds documentation of the branch names and intended development process.

Also cleaned up some verbiage, updated "PKS" references to "TKGi" and "PAS" to TAS", and tightened some line breaks.

... and included a link to the Platform Automation this is intended to be used with.

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this. Unfortunately, the Pivotal Tracker project is private so you may be unable to view the contents of the story.

The labels on this github issue will be updated when the story is started.

[anEXPer]

I fixed the typo because JT prodded me via text message. What a world!