Remove memoization from to_s and to_param
Remove memoization from to_s and to_param

Seems like it could be dangerous if anything that used these modified
them in place

carlthuringer/flipper,carlthuringer/flipper,alabeduarte/flipper,gdavison/flipper,jnunemaker/flipper,alabeduarte/flipper,jnunemaker/flipper,jnunemaker/flipper,alabeduarte/flipper,carlthuringer/flipper,gdavison/flipper,gdavison/flipper,gdavison/flipper,jnunemaker/flipper,carlthuringer/flipper,alabeduarte/flipper