[Bf-codereview] Radial control RNA update (issue4280080)

[NicholasBishop at gmail.com]

Reviewers: bf-codereview_blender.org,

Description:
Patch to make the radial control more generic with RNA.

In the current radial control code in trunk, generic parts of the radial
control are implemented as an incomplete operator within WM. Then each
different user of the radial control has to implement a separate
operator to actually pass in specific brush data -- e.g. sculpt's brush
size, vpaint's brush size, etc.

This patch removes all the extra operators and makes the WM operator do
everything. It now takes several RNA path strings as its properties --
the only required property is data_path, which specifies the data to be
modified by the radial control. The other paths affect display in
various ways, e.g. rotation, color, etc.

In addition to decreasing some duplicate paint brush code, these updates
make it pretty easy to enable radial control for other purposes (and it
can be set up entirely though python or keymaps, no extra C code
needed.)

Please review this at http://codereview.appspot.com/4280080/

Affected files:
   source/blender/blenkernel/BKE_brush.h
   source/blender/blenkernel/intern/brush.c
   source/blender/editors/physics/particle_edit.c
   source/blender/editors/physics/physics_intern.h
   source/blender/editors/physics/physics_ops.c
   source/blender/editors/sculpt_paint/paint_image.c
   source/blender/editors/sculpt_paint/paint_intern.h
   source/blender/editors/sculpt_paint/paint_ops.c
   source/blender/editors/sculpt_paint/paint_vertex.c
   source/blender/editors/sculpt_paint/sculpt.c
   source/blender/makesdna/DNA_windowmanager_types.h
   source/blender/makesrna/intern/rna_brush.c
   source/blender/makesrna/intern/rna_sculpt_paint.c
   source/blender/makesrna/intern/rna_space.c
   source/blender/windowmanager/WM_api.h
   source/blender/windowmanager/intern/wm_operators.c