(Gitlab wants it to be called CONTRIBUTING.md)

Implements the changes recommended by Jan Harms in https://git.ligo.org/rana-adhikari/CryogenicLIGO/issues/45
Fixes #18

Add better description about IO, and clarify some of the argument help.

Add ability to load a noise budget previously saved in an HDF5 file.

If an HDF5 file is passed to the --save option (indicated by '.hdf5' extension)
then save the data to an HDF5 file without plotting.

Functions to save/load noise traces and IFO model parameters to/from HDF5
files.  Requires the h5py module.

free up the "util" namespace for other purposes not related to noise
calculation

namespace conflict with the gwinc plot keyword argument.

automatic creation of the commad line interface script

So that distribution packages and tarballs don't misrepresent what the
project is.

fix name, version and included files

no functional change

Use the new CBCWaveform interface in the insprial_range package for specifying
the waveform and parameters, both in the CLI and test.

Use 'plot' instead of 'fig', which can be confused with matplotlib
figure.

and update README