UI

* Fix buttons jumping around when resizing and zoom. Part of this was
  adding a tiny a 0.001f offset in UI_view2d_view_ortho, otherwise the
  rounding is unpredictable (used to be 0.375f, but that was disabled).
* Fix various issues with zooming, panning panels.  V2D_LOCKOFS_X/Y is
  now taken into account in more places in the view2d code, to avoid
  zooming into the center or panning out of the view.
* Remove "Free" align mode in buttons window (it's not really useful).

* View3D/Graph/Image editors now use the same PanelType system as the
  buttons window, means some deprecated panel code could be removed.
* Some small visual tweaks for panels.
* View 2D Reset operator (Home key), to reset zoom and panning for panels.

* Added argument to set number buttons as sliders (slider=True for itemR).
* Ignore labels for button alignment (doesn't look right).
* Fix some use of context.main in py scripts, should get data from active
  object instead.
* Fix autotexspace -> auto_texspace in py script.

release/ui/buttons_data_lattice.py

@@ -15,7 +15,7 @@ class DATA_PT_lattice(DataButtonsPanel):
 	__label__ = "Lattice"
 
 	def draw(self, context):
-		lat = context.main.lattices[0]
+		lat = context.active_object.data
 		layout = self.layout
 
 		if not lat: