Not true.
Documented ImageLayer, made setImage() fluent.
There's no benefit to surface being non-final in here.
Bye bye HTML DOM backend. You won't be missed (by me anyway).

Anyone who needs the HTML DOM backend, feel free to fork PlayN at the commit
prior to this one and maintain it yourself.
Moved repeatingness into Image and out of ImageLayer.

This eliminates one potential cause of wackiness (that undoubtedly no one ever
ran into) which is that the same image could be used in a layer that repeats in
x but not y and in another that repeats in y but not x and the image would end
up repeating one of the two ways (depending on which was drawn first).

This also makes it possible to draw a repeated image in a Surface by just
drawing the image at a larger size, instead of having to do the cumbersome
combination of setFillPattern and fillRect.

It also allows Image to avoid using unnecessary GPU memory in the case of
repeated images. Previously they would resolve the unrepeatable texture (which
is needed to create the repeatable texture) and then leave it in memory because
it wasn't easy to know whether the image would be used for repeatyness or not.
Now an image *only* has either a repeatable texure or an unrepeatable texture.

Lastly, it simplifies some things for a forthcoming change which will introduce
SurfaceImage (which will further simplify the API and allow surfaces to be
shared between multiple layers, which is currently not possible).

This does prevent code from using the same image as a repeating image and a
non-repeating image, but I highly doubt anyone is doing that. If you are, just
make a copy of the image.