Merge pull request #40 from md5/add-prefix-suffix-functions

Add functions to handle string prefixes and suffixes
Fix typo in test name
Add "keys" function
Document "keys" function
Add support for TLS

* New parameters: -tlscert, -tlskey, -tlscacert, -tlsverify
Add basic documentation for TLS flags
Update GLOCKFILE to latest go-dockerclient
Merge branch 'tls-support-2nd-attempt' into develop