Python modules for BOUT++ pre-processing

Open for further testing
README update

include execution info
Update to the create_grid.py

Corrected the manipulation of contour lines for when there are more
than one contours for the same value. It works both ways now. There
must be a more elegant way to do this.
Update to create_grid.py

Proper fix for the previous error.
Update geqdsk.py , analyse_equil_2.py

The xlim variable was wrongly read from edit files. Consequently
workflow.py changes.
Correct a bug in Analyse_equil_2.py
Merge branch 'master' of git://github.com/brey/BOUT-dev into brey-master
Merge branch 'brey-master'
Merge branch 'master' of git@github.com:boutproject/BOUT-dev