[Fluxus] texture dimension

[gabor papp]

hi Kassen,

> The first step would probably be to poll the texture for it's dimensions in
> pixels. It looks like we can't do that.
you can do this with (load-primitive), (pixels-width), (pixels-height) 
and (pixels->texture). although it's cumbersome.
i have been missing (texture-width) and (texture-height) also, added 
them to git. thanks for the request.

best,
gabor