[Bf-python] bugs in BPython api - fix before release.

[Campbell Barton]

Hi All, There are some bugs to fix in the BPython api and should 
probably be done before the 2.37 release.

 I submitted a patch to fix angleBetweenVecs, Joseph was working on 
mathutils but if his code isnt ready for 2.37 then would sombody review 
my patch?

Another is that new nurbes curves generated by python have all hidden 
verts by default, this is confusing, points in the curve need to be set 
visible.

Fix all broken URL links in the documentation. (I have a patch for 
Blender,PGL on the tracker)

Draw image functon will, for no logical resion, fail to traw images if 
the boarder is > 50% of the screen. hoz/vert. or if the window is 
smaller trhen the image.
see..    
https://projects.blender.org/tracker/?func=detail&aid=2476&group_id=9&atid=125
Example code included.


- Cam