Merge pull request #650 from tuhdo/master

Add more types of tags to be displayed to helm-semantic
* helm-files.el: Fix tramp anoyances (#648).
(helm-find-files-input): Bind non-essential and don't try to input
remote files.
(helm-find-files-1): Use file-remote-p on TAP.
* helm.el (helm-follow-mode): Don't start when empty source.
* helm-files.el (helm-dwim-target-directory): expand-file-name (#653).
* helm.el (helm-match-functions): Fix when match fn is a lambda.
* helm-files.el (helm-find-files-initial-input): Bind ffap-machine-p-known (#648).
* helm-files.el: Bind C-c r for ff as root (#655).