* implemented user buffer binding (now mandatory) and automatic setting of kernel parameters and automatic creation+handling of transformed user buffers (transform program output)
 * additional restriction: user buffer names must be unique across the used transform and rasterization program
 * exact index range must be specified now every time when making a draw call (since the index buffer is a simple opencl buffer now, the necessary information is not available any more)
 * oclraster simple sample changes: uses custom shaders now + added random light color, changing light position and rotation of the model (uniform buffers are updated every frame)