Frontend-rewrite

Lots of changes.
* New lightncandy and storer from vendors.
* Template updates for lightncandy improvements
* Compiled PHP templates moved to handlebars/compiled subdirectory
* New flow-api.js module.
Depends on Mantle extension with handlebars support.

Change-Id: I56ab02691a75c3e2cf522604155cf8f19ba21e86