remove unused imports
update levels tests (disable remapping)
fix for map corners; unify pyplot calling
Add grid
set colorbar orientation via AREA setting
support icon-grid input even on limtted area
Fix auto-limit for box input w/o remapping, new option ASPECT

with the new option ASPECT, the size of the map can be set. See
http://matplotlib.org/api/axes_api.html?highlight=set_aspect#matplotlib.axes.Axes.set_aspect
for possible values, default is 'auto'.

test added