plotting default map_region is 'default'

[jdavid]

Main change: If the map region is not given to the plotting functions, then the 'default' map region will be used. Before an type error was raised.

Other changes: use argparse in in small-plot.py, minor cleanups.

[coveralls]

Coverage increased (+0.2%) to 53.839% when pulling 46e9011 on jdavid:master into 0a24fb9 on spectraphilic:master.

[coveralls]

Coverage increased (+0.2%) to 53.856% when pulling 4616986 on jdavid:master into 0a24fb9 on spectraphilic:master.

[coveralls]

Coverage decreased (-2.2%) to 51.441% when pulling 9b1f8b3 on jdavid:master into 0a24fb9 on spectraphilic:master.

[coveralls]

Coverage decreased (-2.2%) to 51.423% when pulling eb6b72a on jdavid:master into 0a24fb9 on spectraphilic:master.

[coveralls]

Coverage decreased (-2.5%) to 51.138% when pulling a379249 on jdavid:master into 0a24fb9 on spectraphilic:master.

[coveralls]

Coverage decreased (-2.5%) to 51.138% when pulling a114d09 on jdavid:master into 0a24fb9 on spectraphilic:master.

[coveralls]

Coverage decreased (-2.5%) to 51.138% when pulling 569adc8 on jdavid:master into 74433da on spectraphilic:master.