CSS group 'all' and 'false' should be considered as the same

Default WP CSS has group 'false' or 0, which is different from not passing a group when enqueuing a script - as this will default to 'all'

This causes the files to be proccessed separately. So i am just setting all empty 'args' to 'all'

This is a bit quick & dirty really, so i'll have a think about it some more.