Add rehash system config
Merge branch 'develop' into feature/rehash

* develop:
  Remove develop build status from readme
  Remove develop from travis branch build list
  Add enterprise admin secure URL expectations
  Add community admin secure URL unit tests
  Cause admin secure URL hash to use fast hash for obvious perf reasons.
  Inital fix for admin secure urls
Initial, POC implementation of customer password rehash
Ensure consistent options when evaluating rehash
Add customer rehash unit tests
Merge branch 'feature/rehash' into develop

* feature/rehash:
  Add customer rehash unit tests
  Ensure consistent options when evaluating rehash
  Initial, POC implementation of customer password rehash
  Add rehash system config
Add develop back to travis build branches
Update README with rehash info