ENH: more verbose reporting in case of failures to run benchmarks

previously problems in setup stage were completely veiled making it
difficult to troubleshoot lack of results
ENH: carry a copy of pstats.py from python 2.6.7 for systems lacking it
Merge remote-tracking branch 'origin/master'

* origin/master:
  added BenchmarkSuite discovery
  FIX: return array of revisions
  PEP8 all over
  FIX: default run_option and docstring
  ENH: option to run only the latest commit
  add always_clean option

Conflicts:
	vbench/benchmark.py -- pep8-ification, fixed in our changes
Merge pull request #19 from yarikoptic/master

ENH: more verbose reporting in case of failures to run benchmarks