Update experiment README
Add call() function, rename load() function

Slowly encapsulating the run_hydrotrend.py script used in
the Dakota experiments.
Add is_in_path() function
Refactor module, creating HydroTrend class

This will allow the Python script that communicates with Dakota
to become more modular.
Refactor, modularize using HydroTrend class

The HydroTrend class in dakota_utils.models.hydrotrend lets
me break out the actions that were being repeated in the script.
Update parameter values in dakota.in
Suspend unit tests for dakota_utils.models.hydrotrend

After refactoring, there's a lot that needs to be worked out.
Remove TODO item

The permissions set on input and output directories are OK.
Start adding unit tests for HydroTrend class

There will be many.