Updated scanEIT.py to that it accounts for both circular polarizations.

Also refactored the script slightly so it can be invoked directly without a call to python.
Also also added command-line option to specify output plot filename.
Merge pull request #2 from dihm/upstream-hotfixes

Updated scanEIT.py so that it accounts for both circular polarizations.
Merge remote-tracking branch 'upstream/master' with master branch.