[Bf-committers] Patch to add "Show/hide 3D Cursor" functionality

[Dima Glibitsky]

Adds a View3D setting to hide 3D cursor.

In python: SpaceView3D.show_cursor
In C: V3D_HIDE_CURSOR (#defined as 16 for v3d->flag)

This feature has been long requested by some users, the main
motivation being that 3D cursor distracts them during the
sculpting/painting process:
http://blenderartists.org/forum/showthread.php?243932-Hiding-3D-Cursor
http://blenderartists.org/forum/showthread.php?266381-Turn-off-3d-cursor
https://www.youtube.com/watch?v=Q5SqZz9PTlQ

Patch tracker page: projects.blender.org/tracker/index.php?func=detail&aid=35685
The patch: http://www.pasteall.org/42942/diff