Made a test for using Cython
Use typed memoryviews for Cython arrays.

Convert the "old-style" syntax for converting Numpy arrays
to Cython / C arrays to use memoryviews instead. (See
http://docs.cython.org/src/userguide/memoryviews.html for
more information.) This cleans the code and, in some cases,
can improve performance.

Update the setup script as well.
Have to return a numpy array to python, not a memoryview; also fixed string->number in file parsing
Had to specify int32 to avoid type errors
Fortran <-> Cython <-> Python works
Deleted setup.py, building handled by makefile now
Gave read_mesh a more sensible name, sigma_wrapper
Fixed comments for poisson_solve
glue code can now take an arbitrary RHS vector to pass to SiGMA
Added some comments
Changed some names in the 'python-interface' example, which isn't really a python interface anymore
Changed the old 'python-interface' folder to 'c-interface'
Moved 'cy' to 'python-interface'
Added a 'mesh' target to makefiles