Raspy-cal

Got the demo project working properly with SI units and uploaded an up-to-date executable.

Added SI units checkbox to Raspy-Cal. With SI units enabled, it will convert USGS data to SI but assumes that stage file and HEC-RAS project units are correct.

In addition to minor changes, Raspy-Cal is now available on PyPI.

Raspy-Cal still assumes that HEC-RAS and the input data are using Imperial units. However, it can be set to have SI outputs by running it with the argument `METRIC`.

Made datum adjustment optional. I believe this was the last critical barrier to general use; all remaining points (e.g. multi-flow-range calibration) are convenience features.

The attached Demo.zip includes everything needed to try out Raspy-Cal: an example project, a stage file, and configuration files for use with the command line and importing into the GUI. The stage file is based on the results from the example project with variations added to simulate real data that will not perfectly fit Manning's Equation.

Added browse buttons to GUI.

Added automatic flow data application (no need for the user to set flow data in HEC-RAS) and automatic flow data retrieval from USGS stream gages. Also set up configuration files specifying most project information, allowing re-running the calibrator with minimal need to re-specify information. The tool can now be said to be convenient for general use. The only convenience feature still lacking is multi-target calibration.

Flow profiles are now automatically prepared from the stage data file.