pingo. Cosmetic change to render impl

Rename execute command method to draw.
pingo. Changes to render geometry.

Move set state implementation to a separate render geometry state functor.
pingo. Change render geometry indexed implementation.

Change render geometry indexed to use render geometry state instead of deriving from render geometry.
Render geometry indexed is now derived directly from render impl.
pingo. Add loading, creation and of indexed geometry.

Add loading indexed geometry.
Add a is indexed method to geometry.
Add creation of render indexed geometry.