Ajax calls for "files" and "files_trashbin" apps

Frontend:
- The files app list now uses ajax calls to refresh the list.
- Added support the browser back button (history API).
- Added mask + spinner while loading file list

Backend:
- Added utility function in core JS for parsing query strings.
- Moved file list + breadcrumb template data code to helper
  functions
- Fixed some file paths in trashbin app to be similar to the files app
fixing no-repeat for IE8
calling replaceSVG() to display breadcrumb images correctly on IE8
fixing breadcrumbs on ajax loading of files
update file summary on ajax file list load
Added missing "files" JS to files_trashbin module

The recent refactoring for the breadcrumb resizing relies on the "Files"
object which is in the "files" Javascript file.

This fix includes it here as well.
Fixed ajax support to also update the current dir permissions