Another huge commit!!!

First, check on the new files, which are listed below.
The new butspace.h is a local include, only to be used for the buttons
drawn in the buttonswindow.

- editbuts, animbuts, gamebuts, displaybuts, paintbuts,  work now
- i quite completely reorganized it, it's now nicely telling you what
  context it is in
- sorting error in panel align fixed (tabs were flipping)
- align works correctly automatic when you click around in Blender
- editsca.c renamed to buttons_logic.h
- button names are truncated from the right for allmost all buttons
  (except text buttons and number buttons)
- while dragging panels, you cannot move them outside window anymore

And of course fixed loads of little bugs I encountered while testing
it all. This is a version I really need good test & feedback for.

Next step: restoring material/lamp/texture/world

source/blender/src/previewrender.c

@@ -76,6 +76,7 @@
 #include "BIF_gl.h"
 #include "BIF_screen.h"
 #include "BIF_space.h"		/* allqueue */
+#include "BIF_butspace.h"	
 #include "BIF_drawimage.h"	/* rectwrite_part */
 #include "BIF_mywindow.h"
 #include "PIL_time.h"