[Bf-python] adding Blender.ReshadeAll method

[bmx007]

Reshading need indeed  CPU, so there is good reason to not do it automatically.
Adding an argument in one of the Redraw function is finally  a bad idea
because if you want to refresh lamp panel and 3D view, you'll need to
a RedrawAll.
We should add in this case reshading in the RedrawAll. This force
everyone thatr wants to reshade to redraw all the views.

Becauses this need is very specific (we need it only if we change lamp
settings or move object in shaded mode), I think a separate method
will be more flexible.
Perhas a Blender.Object.ReshadeAll (as jms suggests)  will fit ...

Other idea ?