Add Odin, Antima Comet, and several aliases

Added Odin and Antima Comet (which were missing), as well as several unit aliases including
shorthands, non-standard plurals ('animi', etc.), and a few British
spellings ('Cauteriser,' 'Synthesiser', 'Defence Grid'), as well as correcting 'Meches'
to 'Mechs' in two instances.