Tried to fix problems with passing callable objects to GridData and grid_function.
Tried to fix problems with passing callable objects to GridData and
grid_function.

Introduced a new PlotItem, GridFunc.


git-svn-id: a9b3423f80f97d8686891a9c593c60a3eca95014@116 67c13c2a-ce2d-4362-9fbd-a73952e22801

keszybz/gnuplot-py