Make Tiles constructor accept tile map image as input

[quinton-ashley]

The Tiles constructor currently only accepts tile maps in the form of a string or array of strings.

In addition, it should take an image as input. sprite.tile and group.tile could be set to a color.

Example use:

let tileMap = loadImage('tiles.png');

let groupA = new Group();
groupA.tile = '#ff0000';

new Tiles(tileMap);

New groupA sprites would be created corresponding to blue pixels in the tile map image.

Also if sprite.tile was set to a tile character it could use the default palette colorPal color corresponding to that character.