added a check for preprocess_css setting, module is only active if preprocessing of stylesheets is enabled
added a helper function to check if the module should to it's magic on the current page or not
fixed a problem with path_get_admin() function, function can't be called in hook_boot()
added a check to the active check function to check if path_is_admin() function exists
modified the active check to check if path is NOT a admin path
added admin interface (extends /admin/config/development/performance), added caching system, some minor changes and optimizations