GUI implementation progress, adding tilesets and plugins

This pull request adds the following:

* Adding a bunch of tilesets for map building.
* A terrain tileset has been added to interface with tile-based stats. I've arranged them as they are coded:
[plain, fortress, forest, mountain, sand].
* A functional button is finally added. When the unit has finished moving, a button will pop up saying "Wait". Once the player clicks, the button disappears and the next unit can now move. 
* I've added the camera plugin, which we used in smw-koopa-krisis. This camera allows us to focus the camera on the active player, therefore eliminating the screen from scrolling to the "black areas". More on this later, as it will need some work to configure it for our game. 
* Removed test code for the button in main.js, and updated the records.txt file.