elpy.el: Remove the minibuffer-completing web documentation.

This was a cute attempt to get documentation. It'd be much more
sensible to hook into pydoc better.
python-check.sh: Remove pylint.

Pylint is not so much a tool to get a quick idea of bugs in your code,
but more a tool to give you a ton of possible problems that you need
to check individually. It's not useful for what python-check.sh is
supposed to do. So, begone.
README.md, elpy.el: Truncated considerably and moved to the wiki.

Most documentation from README.md and elpy.el was moved to the wiki.
elpy-use-cpython: New function, complement of elpy-use-ipython.
elpy-installation-command: Don't do a user install in an virtualenv

When we have an active virtualenv, omit the --user option to pip
or easy_install.
virtualenv: Advice virtualenv-workon to restart the backend.
elpy-rgrep-symbol: New function.

Search for symbol at point in the whole project. Either finds
all occurrences, or with a prefix arg, only definitions.
yas-trigger-key: Renamed to be in conformance with yasnippet 0.8