*Brush option "size" had different naming in 3D View / Image Editor.
Ported back name "Radius" to RNA (Brush and ParticleBrush)
Discovered by Bart Crouch. Thanks!
ui/ --> startup/bl_ui
op/ --> startup/bl_operators
scripts/startup/ is now the only auto-loading script dir which gives some speedup for blender loading too.
~/.blender/2.56/scripts/startup works for auto-loading scripts too.