*change font
*wipes between game states
*make levels specify gridw instead of gridsize
*make levels default to gridsize of previous one
*bug - things not x snapped to grid sometimes?!
*animated bg on title screen
*help text for all existing levels
*Store level progress and hiscores using localstorage
*new thing type: goats
*goat help text.
*level select screen needs "back to title"
*mechanism to force at least one of a given thing type on a level.
*better level complete animation - zoom in random cat picture.
*only redraw screen if dirty!
*switch to "star" system for unlocking levels
*fix bug when calculating whether there are any valid moves left
*fix bug in random thing selection
*animate chomps
*offset entire grid downwards to allow space for a header
*add images
*award points for stuff
*show score up the top
*animated points gaining (text fading out)
*touch events:
* touchstart: a finger is placed on a DOM element.
* touchmove: a finger is dragged along a DOM element.
* touchend: a finger is removed from a DOM element.
Rob Pearce
rob