update to cryptography 1.6, lxml 3.6?

[rhoerbe]

An upgrade would have among others following benefits:

• cryptography 1.6 includes support for sierra and wheels include openssl 1.0.2i.
• use of system-site packages from python3.5 via macports (which are on 1.6)
• macports inclused also lxml==3.6.0 for py35

[kislyuk]

The cryptography dependency range constraint should be fixed in 6482670 which I just released. lxml was already at 3.6.0.

[mbarrien]

This should be closed now by #84 and #85.