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.
