Mass and Areal Loading

Beginning of new mass & areal loading rates.  These are changes from Will,
still pretty raw, not yet outputting correctly.
Refactoring to functions

Pulled a couple of scripts & a (repeated) part in two other scripts into
functions into a new file.  Deleted the unnecessary lines of code &
scripts.
Revised criteria plots

Updated calculation of points that exceed criteria.  Flagged data no
longer counts as an exceedence.
Better criteria plot

Criteria plots now *actually* account for flagged data.  Also changed the
color to a nice, fire-engine red for exceedence values.