While dividing previously spared me from a lot of work and problems
it is probably best to have everything working for every or as many
platforms as possible. Some platforms fail to provide good ways
to support everything (e.g.:X11 does not have pixmap clipping with
different width/height or alpha-blending) but all OpenGL demos
outside allegro (needs some additional work) should be able to run.
Previously it was not possible to control the visibility or rather
the transparency of all render vertex buffer output. For that to
change another settings was added to zr_convert_config to control
the visibility. To achieve the same result as previously it is now
required to fill that property with 1.0f. To make all GUI element
as a whole more transparent a value between 0.0 and 1.0 can be
selected with 0.0 being completely hidden and 1.0f completly
visible.
