Fix obsolete function

The helm-files-match-only-basename function was deleted from
helm-utils.el at 2014/12/07.
Add `helm-ghq--files-match-only-basename` to match
Fix required helm version to 1.6.5
Fix problem action is nil
Refactor
Merge pull request #7 from masutaka/fix-match

Fix void function `helm-files-match-only-basename`