SRB2 Paint (+Conway's game of life)

[Reusable] SRB2 Paint (+Conway's game of life) 1.3.1

* The -fill parameter now works with canvas_drawcircle, it is not 100% accurate due to technical limitations
* Fixed bugs with commands when giving invalid arguments
- Removed the ability to load an image to the canvas in netgames, to avoid desynchs
+ added canvas_drawcircle
+ added Conway's game of life, toggable with canvas_togglegol

Edit: just realized I forgot to make the -fill parameter work with canvas_drawcircle, gonna fix it asap
* Greatly improved how loading an image works, allowing it to read correctly way more images, they need to be resized to 320x200 though
+ Added level select picture for White Canvas Zone
+ WCZ can also be accessed from any level select now
* The map will be forced to WCZ now, other maps would just be the same canvas but with lag either way
+ Added Experimental netgame support, its not perfect yet, and some desynchs/issues may still happen