hack: support multiline sprite sheets

This is sort of a hack but I'm growing the main container and the "myCanvas" height to 1024px,
which allows for multiple lines of a sprite sheet to be shown at the same time.

TODO, make these hieghts dynamic based on the source sprite sheets.

Does not support animations that span multiple lines.

Example sprite sheet:
  http://opengameart.org/sites/default/files/horse_1.png