code: function(func, context){
              for(var x = this.width - 1; x >= 0; x--){
                  for(var y = this.height - 1; y >= 0; y--){
                      var val = this.get(x, y);
                      if(context){
                          func.call(context, val, x, y);
                      } else {
                          func(val, x, y);
                      }
                  }
              }
          }
docs: Loops over each coord value.
  @method each
  @param {Function} func - A function to call on each coord value. (function(value, x, y){})
  @param {Object} [context] - Context to call the function with (func.call(context, val, x, y))
  @return {Array2d}