Provide informative naming and comments in the configuration file

[awickert]

Currently, the configuration file's contents include some unclear language. This includes:

• #used in filenames: (How? Sometimes input path, sometimes a portion of the filename, ...)
• outfilename: Seems rather to be outfileprefix
• #1 if you are supplying a starting water table, 0 if not: So what happens if not?

Including an annotated example of this config file in the README could be very helpful for model users.

[KCallaghan]

@awickert, I have added more on this in this commit. Was this enough to help?

[awickert]

Much of the shorthand remains ambiguous. For example, "used in filenames" (you have multiple file names); "text file" (what does this do), etc. The hard part about help documentation is that you have to forget all that you know in order to write it. I'll take a pass.

[awickert]

See my edits: 5d3411c. Outstanding questions:

• as well as iteration or time step: The README has "iteration"; do you mean either, or do you mean time step?
• Does your output give depth to water table or water-table elevation? I assumed that you're correct in stating the former in the README, but want to check.
• "outfilename {The name of your output depth-to-water-table file in geoTiff format.tif}" (in the README). Now it is a prefix. Could you update this in the README and in the WTM config file, and share how it works?
• You now have 3 types of model runs; I guess that this is another good reason to give the README a careful update
• It looks like the times are used just in the input files based on my quick read of the code, with output files having "cycles_str", which is an arbitrary counter. Correct my edit if I'm wrong.
• Note that I've changed "filename" to "file path"
• The description of "maxiter" isn't that of a maximum. Clarify?
• How does "total cycles" relate to transient runs and time steps? Perhaps describe.
• for textfilename and outfile_prefix, are these just saved to the current path?
• This remains unaswered from above: #1 if you are supplying a starting water table, 0 if not: So what happens if not?
• Also in regards to this, how is the water table supplied? Is this just another suffix item connected to the input path?

I have also updated these, but think that they need a more precise description. Where in the equation do they go? Are they a coefficient, exponent, e-folding depth, ...?

# Model parameters
fdepth_a           200                      # e-folding depth for transmissivity calculations
fdepth_b           150                      # e-folding depth for transmissivity calculations
fdepth_fmin        2                        # e-folding depth coefficients 

Describe what comes after the prefix

# Model output file names: depth to water table
outfile_prefix     Your_filename_here_      #