Drainpipe A16

The development of koth_drainpipe has been my first full dive into Hammer and TF2 mapping. The map is being developed with Highlander in mind, as that is the format I play the most, but I hope to be able to balance it for most competitive play if possible.

NOTE: everything is still early in development and is subject to change, subtly or drastically.

Additional Credits:
- New concrete textures by SnickerPuffs
- Whiter BLU computer walls by AlexCookie
- RED corporate logo by Void
- Additional signs by Ravidge