Run global-init from elpy-mode.

The global-init method of modules is a lot more important now, and
some modules simply fail to work if it's not called, so make sure
to run it before running buffer-init.
Add coverage targets to Makefile.

Also fixes one misnamed file that the Elisp coverage check
discovered. Which is kind of the only thing this ghetto
coverage tester can find.
Run global-init from elpy-enable again.

It's useful to do this from this method in addition to doing it
from elpy-mode, as this allows users to call elpy-enable and then
modify things Elpy modules have customized.
Configuration display now shows the syntax checker, too.

When the syntax checker is not found, offer installing flake8.

This implements the last part of #146.
Support Python code being shipped with the Emacs Lisp package.

The Elpy Emacs Lisp package now ships with the Python code, and
uses that for the RPC process if it's available.

Implements #147.