Homepage should be updated

[sglyon]

We should update the first paragraph on the landing page of xdress.org

Right now it reads:

XDress is an automatic wrapper generator for C/C++ written in pure Python. Currently, xdress may generate Python bindings (via Cython) for C++ classes & functions and in-memory wrappers for C++ standard library containers (sets, vectors, maps). In the future, other tools and bindings will be supported.

We should mention the types of C things it can wrap in addition to the C++ ones.

I would do this, but don't have time at the moment and didn't want to forget about it

[scopatz]

So what is at http://xdress.org is and should be the docs for the last release. So right now this is the the v0.2 docs. The latest, or dev docs, are instead available at http://xdress.org/latest

Feel free to adjust any of this text. It is located in docs/index.rst