ssh: Remove derived file from git
Returning the actual reason why key exchange failed
Error msg to be returned together with Key exchange failed
Added event/3 and clarified error message
Versions and appup ssh, R16B
Fix doc for ssh:connect/3,4

* Refer to ssh_connection instead of ssh_connect
* Add 'seealso' tag linking to ssh_connection:session_channel
Update copyright years
Prepare release