Add debugging console

Resurrects TTS's wonderful console ;)

It has:
- a cursor
- left/right seek support
- left/right hold-down fast seek support (i.e. key repetition emulation)
- backspace support with repetition support
- delete support
- home support
- end support
- 10 lines of command history
- semi-transparency
- letter P hotkey to open it
- hooks for plugins to define their own commands
- dragging, resizing
- six commands: help, cls, exec, eval, set, get (great for gml debugging)
- been set up to be disabled by default
- option to show in either in-game menu or in-game

![](http://ajf.me/imagedump/screenshots/gg2/fancyconsole-new.png)