Better multi texture support

[KilledByAPixel]

Several users have mentioned wanting to use multiple tile sets. It would be good to think of a better way to handle rendering and loading of multiple files.

[zbagdzevicius]

+

[KilledByAPixel]

We Have Multi Texture Support!

engineInit now takes an array of images to load instead of just one. it waits for all images to load and stores info in textureInfos using the new TextureInfo class

• that also includes creating the webgl texture if necessary
• other info about each texture can be cached here

Drawing functions used to take a tile index and tile size, now they take a TileInfo object

• a new function tile() can be used to create this object and easily retrofit old code
• this object stores the pixel position and size of each tile for better control
• also a textureIndex can be passed in to use any texture!

Webgl automatically will handle swapping out textures when necessary

• if textures are being swapped often each frame this may effect performance

All examples have been updated using the new system

• platformer example has been set up to use 2 textures