Rename GameInfo.txt to gameinfo.txt
Merge pull request #49 from ntgd/master

Fix 'gameinfo.txt' doesn't exist in subdirectory 'source-sdk-2013/mp/game/mod_hl2mp/'
Check in gitattributes for binaries.

Followup to @TheSeg's comments on 5f08baa.
* Switched the SDK from checked-in projects to VPC, the Valve Project Creator. See the Getting Started document on the wiki for details.
* Pulled in bug fixes from HL2 and HL2MP.
Fixed execute permissions on OSX/Linux scripts and binaries.
Merge https://github.com/ValveSoftware/source-sdk-2013
Merge with upstream fixes