from the current shape mix. The old behavior is still accessable from the
menu as "New Shape From Mix".
Checked with Sergey and Bassam that this is a good change. New users
expect the add shape button to simply add a new blank shape, and get
confused when that is not the case. It is also really easy to
accidentally have other shape information in a new shape when the
"from mix" behavior is default.
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.
