Fix base jar installation

Previously, pyleus-base.jar was installed to sys.prefix + '/share/pyleus/
pyleus-base.jar', and this worked fine when Pyleus was installed in a
virtualenv or via an fpm-created deb. In the former case, the jar was
installed to $VIRTUAL_ENV/share/pyleus/pyleus-base.jar, and in the latter,
it made its way to /usr/share/pyleus/pyleus-base.jar.

However, if a user just ran 'pip install pyleus' on their system, the jar
would actually be installed to /usr/local/share/pyleus/pyleus-base.jar,
even though sys.prefix was just '/usr' when pyleus was executed.

Pyleus would thus look in /usr/share/pyleus and fail when it couldn't find
the base jar.

This change uses the seemingly preferred method of including the jar
within the package itself, and using the pkg_resources module to construct
its filesystem path.

The build step of removing the base jar from a topology jar (since it is
unneeded and takes up space) required modification as well.

Closes #24
Update .gitignore
Remove copy of base jar during 'make clean'