[request] Only create minified assets

hi Emre,
great work on WPFC.

I’ve been using WPfC for years now, and although rare, there have been several times where I may want to still minify/combine static assets (CSS, JS), but not create a static index file.

It would be amazing if this could be accomplished on a per-page basis by extending the <!-- [wpfcNOT] --> for something like this. Perhaps <!-- [wpfcAssetsOnly] --> or something. This way assets are still minified and combined, but we can still have dynamic content.