Static content

[Greg]

Heavy duty sites usually offer two servers: a PHP server for dynamic content and a fast static server (or CDN) for static content. We should add an option to the themes to support that.

[Greg (gregfr)]

Here's my idea:

-> have an option "static root" which will be a url such as "http://static.phpdevshell.org/content/"

-> in the distribution provide two folders: one with various non optimized js/css/png, one with optimized/minimized/gathered files

-> if "static root" is empty, include various non optimized js/css/png like we currently do (helps debugging)

-> is "static root" is not empty, use the optimized files from the static root

-> in debug mode, default install is ok

-> in normal mode, just use the server root as the static root

-> in optimized mode, use another server as the static root

[Greg (gregfr)]

This has been mostly done, so I changed it to "fix commited"