Add map info database. Asset database uses dictionary so that hotload reloads the asset info file and not the path it points to.
Merge branch 'master' of github.com:Facepunch/SandboxGame
Update asset database when file with the correct extension is added or removed
Populate map list from map asset database
Add accessor to addons requires list. Check map info requires list against gamemodes addon requires list before showing it in list