Add additional template functions

closest, coalesce, first, groupByKeys and dir
Update 0.3.6 links
Update docker image to use 0.3.6
Add hasPrefix(prefix,s) and hasSuffix(suffix,s)
List functions in FuncMap and README.md alphabetically
Add trimPrefix(prefix,s) and trimSuffix(suffix,s)
Merge pull request #40 from md5/add-prefix-suffix-functions

Add functions to handle string prefixes and suffixes
Add support for TLS

* New parameters: -tlscert, -tlskey, -tlscacert, -tlsverify
Add basic documentation for TLS flags
Update GLOCKFILE to latest go-dockerclient