UI: State/Render groups only contain those calls

Change logic so that State groups contain only state changes and
Render groups contain only render calls.

Former logic was any call up to the render call would be thrown into the
Render group.

Modified call names for
  process<...>Entrypoint
to
is<...>Entrypoint

for easier comprehensions.

Change the pre-processing if-logic block to check for parent->isGroup()
instead of per entrypoint type since each entrypoint was only doing
something if the parent was a group.

Tested with different settings in the settings dialog and with traces:

debug_khr_matrix.bin
glxgears.bin
glxgears-pushpop.bin
glxgears-unpaired-glend.bin
glxspheres64.bin
mydebug_khr-xtra-pop.bin
mydebug_khr-xtra-push.bin
nested-glBegin.bin