Clean root directory before moving gh-pages docs

Modify gh-pages target in doc/Makefile:
Add line to docs/Makefile to remove the underscore directories before moving
the newly created html to the root directory.
Remove MS windows make.bat file

The current documentation Makefile has moved on and this DOS version was out of
date. I have no way to test windoze .bat files and I see no reason to make to
sphinx documentation on a windows machine.

:note: the sphinx documentation make process depends upon a working `make`!
Replace CONTRIBUTING.md with reStructured text
Change documentation build to use project README

Change the sphinx build process to use /README.rst and CONTRIBUTING.rst as
sections in doc/index.rst. This requires two dummy files in the doc directory
with include directives.

Add link to license from documentation

Add sphinx doc stubs for README, AUTHORS, etc
Clean up docstrings

Remove redundant info in docstrings. Tried to make most docstrings math the
numpy/scipy docstring
format (https://github.com/numpy/numpy/blob/master/doc/HOWTO_DOCUMENT.rst.txt)
which is easier to read in raw docstrings than is the sphinx-specific markup
but still is parsed well by sphinx.
Clean up reStructured text in readmes sphinx files

Make code examples show up correctly in sphinx-generated docs. Minor edits to
README, license, and CONTRIBUTING.