Extracting RAF to a top-level
Make reflected canvas of a smaller size

This change scales down reflected canvas. It also
fixes issue #25 my mapping a part of reflected image
to the drop regarding to its location.
Avoid using setTimeout and employ global rAF instead
fix border problems related to mapping of reflected image into drop
fix indentation: use tabs instead of spaces
tune drop mapping a bit to make it more real
flip vertically mapping inside the drop
Mozilla does not like sw or sh properties of drawImage to be negative