Improvements in file search and spark-suggest-box

File search:
* Sort file search results by file name / path.
* Remove the default count limit on file search results.

spark-suggest-box:
* Put details on a separate line and remove surrounding brackets.
* Use a CSS class instead of an attribute to style the active item: supposedly faster according to some hints from Polymer.

@dinhviethoa

![screenshot from 2014-03-13 14 03 20](https://f.cloud.github.com/assets/5606182/2415352/318d4f7c-aaf4-11e3-880b-87fe9570673c.png)