Removed Play distribution

The Play distribution is no more.  Included in this removal was:

* Removal of skeletons
* Removal of console project
* Removal of all custom SBT setup
* Removal of play and play.bat scripts
* Removal of all SBT tasks related to building the distribution
* Updated the migration guide to document how to obtain Play
Return 400 Bad Request for bad URI encodings on assets
Merge pull request #2496 from gmethvin/assets_uri_encoding

Return 400 for invalid URI encodings on assets
Merge pull request #2539 from jroper/goodbye-play

Removed Play distribution
Renamed Java SimpleResult to Result

Did the minimum (which was a lot) to get the rest of the code compiling.
Removed last traces of SimpleResult and documented it in the migration guide