Improve error reporting.
Merge branch 'master' of https://github.com/USGS-EDEN/EDEN-hydrograph-data
Code cleaning.
Changes per Mary's review.
Unit test.
Merge branch 'master' of https://github.com/USGS-EDEN/EDEN-hydrograph-data.git
New code to calculate flags per clarified requirements.
Merge remote-tracking branch 'master_repo/master'

Conflicts:
	dj_eden_app/hydrograph.py
	dj_eden_app/views.py
merged hydrographs and views
attempted implementation of x-range limits