DM - Tube V2

The map formerly known as dm_tube_dude is now re-released as DM_TUBE_V2.
The map formerly known as dm_tube_dude is now re-released as DM_TUBE_V2 New features in v2: Rideable train added. I didn't have time to implement a train before the DM contest, so this was the main reason for making v2. Includes Valve's new