Added a convar for keeping entities 'on' when empty

- Rewrote the whole addon
- Added strafing
- The choppers now use seats internally
- All convars can now be found under aw2_*
- Gunships have been added
- The hunter chopper's window has been adjusted
- The hunter chopper's gunner seat now has a different camera setup
- Added carpet bombing and rocket pods to the hunter chopper

And a lot of other stuff

Potential fix for trying to enter an entity without a weapon

- Improved chopper handling
- Chopper crashing should be a lot more chaotic now
- Increased the max speed of dropships and allowed them to slide a small amount

Updates physgun usage

Prevents physgun usage in certain gamemodes

Fixed sound issues

Entities are admin only

Initial upload