merge_rrewll: Combine Water Level Records
In mkoohafkan/rremat: Russian River Estuary data collected by the Largier Lab

Combine water level data files into a dataframe.

1 2	merge_rrewll(wll, timecol = "mtime", depthcol = "depth", elevcol = "elev", tempcol = "temp", sitecol = "site")

`wll`	A list of dataframes of water level data
`timecol`	The column name containing matlab numeric datetime. Matlab times are assumed to be in "UTC" timezone.
`depthcol`	The column name containing depths.
`elevcol`	The column name containing elevations.
`tempcol`	The column name containing temperatures.
`sitecol`	The column name to contain site data.