Merge tag 'ssh-transport-0.4.0' into develop

ssh-transport-0.4.0
Updated version for next release cycle
Fix tag prefix in release script
Update .gitignore
Remove old release scripts
Fix group id in readme
Make standoff increase in connection attempts

In order to reduce the number of connection attempts back-off connection
attempts by a constant factor (fixed at 1.5 for now).

Also improves logging of connection attempts.
Use local ssh-agent when :temp-key is true

To avoid temporary keys being added to the system ssh-agent, use a local agent
when :temp-key is true.
Add wait-for-port-reachable options

Allow specification of :port-retries and :port-backoff options.
Remove connection function overload for state
Update to clj-ssh 0.5.4

Includes fixed handling of literal key strings.
Updated project.clj, release notes and readme for 0.4.1
Merge branch 'release/0.4.1'