Add development bootstrapping.
Move tests.
Whitespace.
Simplify tests.
Configure test command.
Remove unused method.
Ignore virtualenvs in git.
Ignore virtualenvs in test harness.
Don't set test directory in pytest.cfg.

Setting the test directory like this means if you provide a test
directory or file on the commandline like this:

    $ ./env/bin/py.test tests/test_node.py

would cause both the tests director and the supplied test file to be
searched for tests.

Instead, rely on norecursedirs to avoid searching for tests in
virtualenvs.
Add pep8 style checks.
Whitespace.