New documentation and (almost) new version

Hi there,

I've updated the website to reflect the states of things a little

     - graph-tool is now a python module, instead of a stand-alone

     - The old stand-alone version of graph-tool is considered
       deprecated. It differs too much from the current version, and
       will no longer be maintained.

     - There is not yet an official release of the library. It must be
       obtained directly from git. I'll do a release once the
       documentation is 100% done.

     - The new documentation is online and ~80% complete.

The plan is to finish this up as fast as possible, and proceed to
include new algorithms (such as flow, new generators, k-core, etc).

Hopefully, things will flow more smoothly from now on.

Testers are welcome. :wink:

Best regards,