Blender Git Loki

Skip drawing of particle systems (including hair) when using cache
duplis.

Particle systems can not be overridden from caches easily, there are too
many strings attached to the data and code to make this reliable.
Instead, a new simplified data structure for reading hair from caches
will be added, which replaces drawing and rendering of particle data.
The original particle data is not updated through duplis, so is usually
out of sync and should not be displayed.