Bugfix Animation current loop count

Bugfix for animation current loop count, if animation shall only play
once and then finish the current loop count is not updated without this
fix.
Bugfix for texture coordinates after object reuse

Add a flag to keep track if texture coordinates are dirty. This is
needed since the texture coordinates may be changed after creation on
some objects.
Without this fix the texturing will be wrong when reusing objects that
have the texture coordinates changed.
Add new highlight material and shader

Add support for a highlight type of material, this can be used to color
the visible pixels of an object in any specific color.
Use for instance in a hit/flash animation when a sprite should be
colored to show that it is hit.
This is the first revision, there may be a more clever way of using
texture color + alpha and the diffuse color. This works for now.