dont allow cycles via not rendering self, and some tidying

much simpler than checking subtree and leaving out the radio option
using has_child query on tree to not have to look them all up
Merge branch 'v7.1' of git://github.com/phpwax/wildfire.interface into v7.1

# By Charles Marshall
# Via Charles Marshall
* 'v7.1' of git://github.com/phpwax/wildfire.interface:
  remove the old form submit styling, fall back to the default one