BPython: bug fixes / patches from trackers

(excuse me for not committing earlier)

Patches by Ken Hughes (thanks for all bug fixes!):

1) Setting a scene's MapOld and MapNew values in python does nothing:
bug #2566 submitted by Dominic Agoro-Ombaka (dmao):
https://projects.blender.org/tracker/?func=detail&aid=2566&group_id=9&atid=125
patch #2571:
https://projects.blender.org/tracker/index.php?func=detail&aid=2571&group_id=9&atid=127

2) Calling the file selector after setting the progress bar crashes Blender:
bug #2418 submitted by Alessandro Garosi (brandano):
https://projects.blender.org/tracker/?func=detail&aid=2418&group_id=9&atid=125
patch #2568:
https://projects.blender.org/tracker/index.php?func=detail&aid=2568&group_id=9&atid=127

3) Menus always generate same event when canceled:
bug #2429 submitted by Campbell Barton:
https://projects.blender.org/tracker/?func=detail&aid=2429&group_id=9&atid=125
patch #2579:
https://projects.blender.org/tracker/?func=detail&aid=2579&group_id=9&atid=127

4) Add a vertex to a mesh with groups using a script and then edit that mesh hangs blender:
bug #2211 reported by German Alonso Tamayo (servivo):
https://projects.blender.org/tracker/index.php?func=detail&aid=2211&group_id=9&atid=125
patch #2580
#https://projects.blender.org/tracker/index.php?func=detail&aid=2580&group_id=9&atid=127

About bug #2033, I'm still looking at it, committing a small fix now.

=====

Patches by Campbell Barton (thanks!):

#2482: BGL pydocs fix broken links
https://projects.blender.org/tracker/index.php?func=detail&aid=2482&group_id=9&atid=127

#2426: Large text in Draw.Text and Draw.GetStreingWidth
https://projects.blender.org/tracker/index.php?func=detail&aid=2462&group_id=9&atid=127

#2521: scene.getActiveObject()
https://projects.blender.org/tracker/index.php?func=detail&aid=2521&group_id=9&atid=127

#2523: NMesh.GetNames()
https://projects.blender.org/tracker/index.php?func=detail&aid=2523&group_id=9&atid=127

- docs also updated

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

@@ -7,6 +7,7 @@ B{New}:
   - L{Scene.clearScriptLinks} accepts a parameter now.
   - L{Scene.getLayers}, L{Scene.setLayers} and the L{layers<Scene.layers>} and
     L{Layers<Scene.Layers>} Scene attributes. 
+  - L{Scene.getActiveObject} method.
 
 Scene
 =====
@@ -189,6 +190,20 @@ class Scene:
        particular scene.
     """
 
+  def getActiveObject():
+    """
+    Get this scene's active object.
+    @note: the active object, if selected, can also be retrieved with
+      L{Object.GetSelected} -- it is the first item in the returned
+      list.  But even when no object is selected in Blender, there can be
+      an active one (if the user enters editmode, for example, this is the
+      object that should become available for edition).  So what makes this
+      scene method different from C{Object.GetSelected()[0]} is that it can
+      return the active object even when no objects are selected.
+    @rtype: Blender Object or None
+    @return: the active object or None if not available.
+    """
+
   def getCurrentCamera():
     """
     Get the currently active Camera for this Scene.