Improve OpenMP support.

* More robust parsing of directives.
* Add support for OpenMP runtime library.
* Handle conflicts with c++ keyword private THXS to Mehdi Amini's report.
* Refactor OpenMP stuff into a new module.
* Improve testbed based on OpenMP Validation Testsuite.
* Distribute a Python binding of libgomp.
Fix a few OpenMP bugs.

* Allow to attach directives on Pass nodes.
* Make sure OMP directives are not lost/misplaced when held by the final
  statement of a block.
Fix sections for OpenMP support
Add sleep function from time module
Add OpenMP tests
Release 0.2.0
Generate website from source informations

Gather informations from the README, doc/* files etc and turn them into
a decent website, hosted at http://pythonhosted.org/pythran/.
Itertools.imap, ifilter, izip and product now supported by pythran.
Transformation of generator expressions into iterators.