Fixes #1470 & static resources being downloaded twice

Hashing of files leads to every static file being downloaded twice.
Once with the normal name & once with the hash added
* Remove resource.hash being added
* All files in public are only added to Cache section
* Fallback can be emtpy in the current implementation.
* app.manifest on L156 removed because it is not necessary
* screenshots & video demo on
(https://github.com/akralj/meteor-appCacheSafariBug)