Expanding on the question in the title:
I would like to find a way (via a plugin) to use timestamps for the JS and CSS file version query strings that are output with wp_register_style and wp_register_script.
I know this can be easily modified in the calls themselves, and I do it this way currently:
$style_mtime = filemtime(dirname(__FILE__) . '/css/style.css');
wp_register_style( 'fstop-stylesheet', get_stylesheet_directory_uri() . '/library/css/style.css', array(), $style_mtime , 'all');
wp_enqueue_style( 'fstop-stylesheet' );
I would love it if I could pass the timestamp portion off into a plugin. I recently found this plugin that does a good job of moving the query string into the filename, which should result in better caching for proxies: https://gist.github.com/ocean90/1966227
And it does work well. I would like to add the timestamp bit in to automate the whole process.
Ideas?