Add more implementations

[fingolfin]

In particular, adding iOS and Android clients might be useful for quite some people. Also, look at the Wikipedia lists:

• https://en.wikipedia.org/wiki/Comparison_of_SSH_clients
• https://en.wikipedia.org/wiki/Comparison_of_SSH_servers

[davidcarver]

Really nice comparison!

Have you thought about adding gsi, hpn, and/or nersc openssh patches to your openssh comparison.
In the last couple of years many of the high performance computing research centers (e.i. supercomputers) are patching openssh with these three additional patches.

[fingolfin]

Thought about it: Sure. But it's a matter of time and priorities... and not knowing much about those patches... pull requests are always welcome, though :). I'd add them formally as separate implementations, so that they appear side-by-side in the comparision.