Gang Garrison Builder 2

Adds a bunch of stuff including:
* Dynamic gamemode and entity loading (making it really easy for plugins to add stuff).
* Built in garrison builder with the ability to instantly toggle between playtesting and building.
* New map saving format that allows custom properties such as scaling and more (see moveboxes and medcabs)
* Fixes moveboxes speeding up faster in 60 fps mode (while also adding a speed property)
* Ajfs GGON
* Cspotcode's dll because ajf told me to.

See thread here: http://www.ganggarrison.com/forums/index.php?topic=35951.0
(the mod download there is not up to date with the repository)

Ps I didn't do A LOT of testing, but everything seems to work.
Because this does the `is_string(key)` thing, you should note somewhere this only works for maps with string keys (like, for example, the maps GGON produces).