Use wheels! yeah!

No more infinite time to re-create a virtualenv.
Merge branch 'kali/use-wheels' into develop
bump version

because we've updated it with mail fw.
Merge branch 'kali/bug/bump-bm-root-version' into develop
Use python2.7 instead of python2.

The binary `python2` is not present on Debian systems.
The common denominator for Ubuntu, Debian, Arch is `python2.7`

Related to #6048.
Merge remote-tracking branch 'refs/remotes/ivan/bug/python2-compat' into feature/package_osx_py2app
Add note to release doc for bundling OSX

Also add recipe for cryptography package