Trying to fix bug reported by Peter den Bak and Meino Christian Cramer (thanks!):

-- splash screen disappeared (duh, I did that!) and Blender quits upon exiting from some 225 games:

It was troublesome to find how to run demos in general with the screen correctly redrawn before they started, etc.  Ended up making the above error in screenmain().  About the games, I don't have them and will need some time to get the files for testing, but I'll do it, though only on linux.

BPython:
-- Window: added GetScreens, SetScreen and improved GetScreenInfo.
-- Object, NMesh: updated (added in NMesh) method getMaterials to return either only valid materials as before or also empty slots (as None).  This previous omission can be considered a bug, since it made info about materials incomplete / incompatible with face mat indices.  Thanks Yann Vernier for bringing this up and sending/proposing a patch that also fixed a bug related to assigning lists of materials with different lengths to obj and its mesh. setMaterials also accepts Py_None entries now, which become empty slots in Blender.
-- doc updates.

source/blender/python/api2_2x/doc/Window.py

@@ -8,7 +8,7 @@ Window
 
 This module provides access to B{Window} functions in Blender.
 
-B{New}: L{EditMode}, L{ViewLayer}, functions related to input events, etc.
+B{New}: many new functions related to screens and events.
 
 Example:
 --------
@@ -360,7 +360,22 @@ def GetAreaSize ():
      returns for the 'vertices' of the same area.
   """
 
-def GetScreenInfo (type = -1, rect = 'win'):
+def GetScreens ():
+  """
+  Get the names of all available screens.
+  @rtype: list of strings
+  @return: a list of names that can be passed to L{SetScreen}.
+  """
+
+def SetScreen (name):
+  """
+  Set as current screen the one with the given name.
+  @type name: string
+  @param name: the name of an existing screen.  Use L{GetScreens} to get
+      a list with all screen names.
+  """
+
+def GetScreenInfo (type = -1, rect = 'win', screen = ''):
   """
   Get info about the current screen setup.
   @type type: int
@@ -373,6 +388,9 @@ def GetScreenInfo (type = -1, rect = 'win'):
         - the whole area: 'total'
         - only the header: 'header'
         - only the window content part (default): 'win'
+  @type screen: string
+  @param screen: the name of an available screen.  The current one is used by
+      default.
   @rtype: list of dictionaries
   @return: a list of dictionaries, one for each area in the screen.  Each
       dictionary has these keys (all values are ints):