Updated version for next release cycle
Add link to clj-ftp in README
Fix :out :stream in the cli namespace

Caller becomes responsible for closing the session.

Closes #29
Lock known hosts file

Try and prevent concurrent read and writes to the known hosts file.
Simplify shell code
Add updated link to scp details blog post
Updated project.clj, release notes and readme for 0.5.11
Merge release/0.5.11