More elaborated tracker-search source

Working towards multiline candidates 'helm-source-tracker-transformer can
handle (DISPLAY . REAL) cells and builds them now.

To make that possible, a new attribute 'source-candidate-seperator (not
yet documented) is queried in 'helm-output-filter--process-source. It
defines the 'split-string SEPERATOR by which the raw output source is
split. This is needed to make the raw candidates arrive in one piece in
form of
"  file:///path/to/foo
  ...foo snippet..."
Another approach for the tracker-transformer

This transformer function works without changes in the process-filter by
saving incoming incomplete candidates temporarily in a variable.
Merge remote-tracking branch 'refs/remotes/upstream/master' into mod-only-tracker
Add github reference for 'multiline issue
Remove test-candidate from tracker-transformer
Improved tracker-transformer

Reduced complexity of the transformer function.
Disabled color for tracker-search output.
Highlight paths with 'helm-highlight-files.
Added github reference.
Merge remote-tracking branch 'upstream/master' into mod-only-tracker

Conflicts:
	helm-files.el
* helm-buffers.el (helm-buffers-list--match-fn): Add filename matching to *buffers-list (#532).
Renamed from helm-buffer-match-major-mode.
* helm-buffers.el (helm-buffers-list--match-fn): Fix typo (#532).
* helm-buffers.el (helm-buffers-list--match-fn): Fix some clauses that was noop.
* helm-help.el: Document new buffer matching feature.
* helm-buffers.el (helm-buffers-list--match-fn): Matching only on directory name is better.
* helm-help.el: Document it.
* helm-buffers.el (helm-buffers-list--match-fn): Allow matching inside after matching on fname.
Merge remote-tracking branch 'refs/remotes/upstream/master' into mod-only-tracker
Moved to cl-loop, removed helm.el modifications
* helm.el (helm--maybe-update-keymap): Don't add a keymap if already there (fix emacs bug#17642).
* helm.el (helm--maybe-update-keymap): Revert previous commit (fixed in emacs-24 branch).
* helm-files.el (helm-ff-transform-fname-for-completion): regexp-quote also bn when cand is a directory (#534).
* helm-files.el (helm-ff-transform-fname-for-completion): concat after 1 char and quote single chars (#534).
* helm-utils.el (helm--mapconcat-candidate): quote single char.
* helm.el: Disable blink-matching-paren.
* helm-files.el (helm-ff-set-pattern): string-match should match pattern not regexp.
* helm-files.el (helm-ff--transform-pattern-for-completion): Renamed from helm-ff-transform-fname-for-completion.