Adds option for strongly preferred prefix and single segment search.

These options make stringMatch produce useful and predictable results in cases that are not
quite the same as file searching (such as code hinting).
Turn on preferPrefixMatches for JS code hints.

Adding this option to string matching provides a fix for #3534 by putting
the matches at the same score and using the scope as a tie breaker.
Extract function to create prefix search result.

...and some other small changes based on review feedback
Merge branch 'master' into dangoor/prefer-prefix

Conflicts:
	src/extensions/default/JavaScriptCodeHints/main.js
Rename singleSegmentSearch StringMatch option to segmentedSearch. Defaults to false
(which is a change in behavior for quick navigate that should actually be fine for
those uses). Also augmented the test cases based on review feedback.
Quick Open plugins can include matcherOptions to set StringMatch options
Merge pull request #3588 from adobe/dangoor/prefer-prefix

Add QuickOpen / StringMatch options for strongly preferred prefix and unsegmented search weighting.