Added .vcds from all the singleplayer games in the SDK
Added skill cfg files so that refilling ammo will work.
Added .vcd files from lost coast
Revised the contribution guidelines to encourage more interaction within the community.
Added bloom shader and screenspace effect helpers as examples for the SDK.
Merge branch 'master' of https://github.com/ValveSoftware/source-sdk-2013
Brought in all updates from Valve.