Moved bfrq from eos80.py to geostrophic.py.
Using the same OMEGA as in the Matlab toolbox.
Added c3515.
Fixed a bug at aonb.
Reversed lon, lat to match the Matlab toolbox.
Reversed lon, lat at gvel to match Matlab toolbox.
Moved smow from eos80.py to library.py.
Added a test to compared with octave results form the original toolbox.