Updated README.md and added requirements.txt

Moved version and license to ssllabs/vars.py

``__version__`` and ``__license__`` are not importable via ``ssllabs/vars.py`` from both ``setup.py`` and ``__inity__.py``. This will prevent errors when importing code during installation before resolving dependencies. Fixes for #10.

Bumped version to v1.3

README.md updated