Merge remote-tracking branch 'features/properpaint' into 2.3.2-staging

This makes sure that painting actually happens at paint events, making
display more fluid.

diff --cc status.23x
index 16ce90b5f885d904a9e4a415234c49a3b3d2693b,16ce90b5f885d904a9e4a415234c49a3b3d2693b..863f74e7fe826899b4c437cfdac1513906a29092
--- 1/status.23x
--- 2/status.23x
+++ b/status.23x
@@@ -25,6 -25,6 +25,11 @@@ What's ne
  
  * USER INTERFACE
  
++- Overhaul the document painting mechanism. Now the screen is updated
++  asyncronously (as all normal applications do), which makes LyX
++  snappier, especially on repeated events. As an added bonus, subpixel
++  aliasing is honored in the work area.
++
  - Handle properly top/bottom of inset with mac-like cursor movement
    (bug 10701).