Blender Git Loki

2.50:
svn merge https://svn.blender.org/svnroot/bf-blender/trunk/blender -r19820:HEAD

Notes:
* Game and sequencer RNA, and sequencer header are now out of date
a bit after changes in trunk.
* I didn't know how to port these bugfixes, most likely they are
not needed anymore.
* Fix "duplicate strip" always increase the user count for ipo.
* IPO pinning on sequencer strips was lost during Undo.