[changeset] - improve clf() compatibility

[Ben Abbott]

I sought to apply the new vectorized version of delete(), but  
discovered that clf() was limited in its compatibility with Matlab, so  
I addressed much of that as well.

To be fully compatible with Matlab, the defaults for the figure must  
be available, so that "clf reset" is able to restore the figure's  
properties to their default values (with the exception of "Position"  
and "Units").

Ben

changeset-clf.txt
Description: Text document