hoon: add +snip and +rear
hoon: add +snip and +rear

Helper functions for dealing with the ends of lists.

ngzax/urbit,urbit/urbit,ngzax/urbit,urbit/urbit,ngzax/urbit,ngzax/urbit,ngzax/urbit,urbit/urbit,ngzax/urbit,urbit/urbit,ngzax/urbit,urbit/urbit,urbit/urbit,urbit/urbit