Basic matchmaking, browser sync

Simple matchmaking for one teacher and one student; no login yet; all
user data hardcoded.  Browser sync implemented with a Session var for
the gameID (_id of record in plG that tracks the current game session).
Refactored data, added tables

Split off guides and dests into separate tables.  Added tables for
tokens (inventory objects).  Changed navigation logic (new nav path
array).  Renamed episode template to fork.  Added placeholder inventory
bar.