Update to Scala 2.10.0, Casbah 2.5-Snapshot, Salat-1.9.2-Snapshot
Add a custom Salat context to fix error of: GRATER GLITCH when Salat
doesn't have access to the Play classloader

Caused by: com.novus.salat.util.GraterGlitch:

GRATER GLITCH - unable to find or instantiate a grater using
supplied path name

REASON: Very strange!  Path='models.Registration' from
pickled ScalaSig causes ClassNotFoundException

Context: 'global'
Path from pickled Scala sig: 'models.Registration'
Merge pull request #1 from jwmatthews/master

Update for Scala 2.10 and associated deps, also fixes a Salat issue of a missing custom context for Play Classloader.