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/editconstraint.c

@@ -41,6 +41,7 @@
 #include "DNA_armature_types.h"
 #include "DNA_object_types.h"
 #include "DNA_scene_types.h"
+#include "DNA_screen_types.h"
 #include "DNA_constraint_types.h"
 #include "DNA_curve_types.h"