Deduplicate and rewrite documentation

The readme file is essentially duplicated. Highly similar content exists at both
`README.md` and `docs/index.rst`. This is problematic: it's hard to maintain two
copies of similar documentation. This makes it easy for errors to creep in, and
demotivates developers from writing documentation. Additionally, the
documentation in the readme could use more polish.

This commit contains the following changes:

* Delete README.md, and create a sylink pointing from README.rst to
  docs/index.rst.
* Rewrite docs/index.rst. Make it include the information formerly provided
  by README.md, add a link to the docs/createtest.rst file, and generally
  rewrite the file for easier reading.

README.rst

@@ -0,0 +1 @@
+docs/index.rst

docs/conf.py

@@ -121,7 +121,7 @@
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ['_static']
+#html_static_path = ['_static']
 
 # If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
 # using the given strftime format.