Add the plot sub-module to setup.py

Without that entry, the package will not install properly from "make install".

--HG--
branch : release-0.7
Added tag 0.7.0a for changeset d05f35cf5a4a

--HG--
branch : release-0.7
Unit test for issue 36.

http://code.google.com/p/pygeode/issues/detail?id=36

--HG--
branch : release-0.7
In plotvar, make a copy of the x/y axes before modifying the axis values.

Fixes issue 36.

--HG--
branch : release-0.7
Re-enable the custom header message for progress bars.

Fixes issue 33.

--HG--
branch : release-0.7
Release 0.7.1

--HG--
branch : release-0.7
Added tag 0.7.1 for changeset e1d3fe822882

--HG--
branch : release-0.7
Merge in bug fixes from release-0.7.
Merge in changes to convert all C functions to Python extension modules.

Note: Running "make" will no longer compile the C code.  Instead, run
"python setup.py build_ext --inplace" after any updates to the C files.