Replace ComparableSet with a Requirements collection
Fix Formula#<=> on trunk Ruby

Arguably this method shouldn't exist and sort_by(&:name) used instead.
libnatpmp: add 20130911 bottle.
libnids: add 1.24 bottle.
libntlm: add 1.4 bottle.
libnxml: add 0.18.3 bottle.
liboauth: add 1.0.3 bottle.
libofx: add 0.9.9 bottle.
liboil: add 0.3.17 bottle.
libopendkim: add 2.9.2 bottle.
liboping: add 1.6.2 bottle.
libosip: add 4.1.0 bottle.
libowfat: add 0.29 bottle.
libp11: add 0.2.8 bottle.
libpcl: add 1.12 bottle.
libpgm: add 5.2.122 bottle.
libpoker-eval: add 138.0 bottle.
libpqxx: add 4.0.1 bottle.
libpst: add 0.6.55 bottle.
libpuzzle: add 0.11 bottle.