Add file cache of minified dependancies

[msigley]

Minified dependancies should be stored locally as css or js files if the file permissions on the server permit it. It is alot faster for a web server to query a local file than a row in the database.

[MickeyKay]

That said, please keep in mind that the symlink method allows for simpler use for sites that utilize multiple servers, across a load balancer for example. It might be nice to add the option for writing to local files, however simply switching to this functionality as the default would likely break things for a lot of users, myself included.