Switch v0.1.2 SD image users to the new v0.1.2 git branch.

This will switch v0.1.2 SD image users currently using the master
branch over to the new v0.1.2 branch.
Allow web UI to load if settings file does not exist.
(cherry picked from commit 4dfa041ffca5cd48226f0af9886cd97995a2b28d)
Add a README.rst file for github.
Add FPP sub-forum link to Readme
Merge branch 'stage'

Start to reclaim master for development use again by
merging all changes from the stage branch back to master.