switch add_filter priority and args from 1, 99 to 99, 1

hi matthias! thanks for writing uf2, i'm looking forward to using it. i'd use SemPress, but i already have another theme set up that i'm happy with, so i'm planning to use this to add microformats2 without changing themes.

i *think* this bug fix is what you meant with the add_filter() calls, based on the add_filter docs (http://codex.wordpress.org/Function_Reference/add_filter#Parameters ). it fixes interaction with another plugin i use that also uses the the_content filter.

thanks in advance!