Documentation in reStructuredText

Hi, Kevin!

I've found that long description on [PyPI](https://pypi.python.org/pypi/btsync.py) looks a bit broken. Basically the reason is that PyPI interprets it as reStructuredText, but not a Markdown. I've just converted it as is to RST. It should look better now.

You may check it here: https://github.com/9seconds/btsync.py/blob/documentation_in_rst/README.rst