There may well be more vertex shaders that need this, but I couldn't find them
in my testing.
Differential Revision: https://developer.blender.org/D4921
Apply clang format as proposed in T53211.
For details on usage and instructions for migrating branches
without conflicts, see:
https://wiki.blender.org/wiki/Tools/ClangFormat
Now handles are drawn using index buffer instead of duplicating memory
requirement.
Also make use of shader tricks to draw handles antialiased, and respond to
UI scalling.
Make vertex point match edit mesh vertex size.