Release Notes for 5/15/2013

[ MAPS ]
- de_train: Fixed grenade collision bug, other minor bugs.

[ MISC ]
- Added a convar sv_vote_allow_in_warmup defaulting to off and controlling whether votes are allowed during warmup.
- Shooting through a nodraw surface now doesn't count as a gun penetration (you can always shoot through nodraw).
- Consolidated Map Groups in Classic Casual and Demolition modes.