New model for Pathfinder Society Organized Play sources

PFS Organized Play sources will now be shown under publisher "Paizo
Publishing PFS". This will partition the PFS Organized Play checked
sources into a separate tree in the UI to help players avoid using
unconverted sources which *might* cause load errors; while not blocking
the user for doing so if they specifically wish to do so. The later case
will likely happen whenever a user wants to experiment with a new source
that hasn't yet been converted to PFS organized play, or with any
incomplete NFD source, or when using their own Pathfinder homebrew
source.
Add KEYs to Curse of the Crimson Throne sources
Fix PUBNAME in core essentials to match others
Corrections to PFS Organized Play Core Assumtion
Fixes to PFS Organized Play APG
Merge pull request #77 from mjmeans/pfs

PFS Organized Play changes