Add pythran benchmark for pairwise

Tries hard to integrate pythran into the benchmark model, and to reuse
existing code whenever possible.
Julia benchmark, as extracted from Kurt's tutorial at scipy2013
Merge branch 'master' of https://github.com/serge-sans-paille/python-benchmarks
Add arc distance benchmark from https://bitbucket.org/FedericoV/numpy-tip-complex-modeling

* The Parakeet is not yet added