Blender Git Loki

Merge branch 'master' into modifier-panels-ui

Only rebuild panels when modifier list changes

Benefits of this:
- Epanding and collapsing modifier panels works
- Efficiency
- Solves other handler crashes

Also renamed modifier_index to list_index for more generality

Remove unecessary changes

Fix more build errors, remove old property from UI

Test before pushing...

Fix build error (typo)

Add commented out C drawing code for modifiers.

Left over from an earlier patch, this layout drawing code still
needs to be converted to be panels.

Use a panel based UI to draw modifiers

Currently an interface template creates a RECREATE panel for each
modifier, which is then drawn with the rest of the panels. The python
based modifier drawing is removed.

This also adds a UIList and the idea of an active modifier, along with
object operations to add and move it.

Add a modifier callback to register UI panels

The modifier UI is defined in each modifier file. This commit only
implements the callback for a few modifiers, with work in progress UI.

New common UI functions handle the common parts of registering panels
and retrieving modifier pointers from them.

Add a RECREATE panel type

Panels built from types with this flag don't have a 1 to 1 correspondence
with their types-- there can be many panels built from a single type. That
can be used to tie each panel to a modifier instead.