Add Odin + several aliases

Added Odin (who was missing), as well as several unit aliases including
shorthands, non-standard plurals ('animi', etc.), and one or two British
spellings ('Cauteriser,' 'Synthesiser'), as well as correcting 'Meches'
to 'Mechs' in two instances.
Add new plural alias for 'Aegis' ('Aegises')
Add Antima Comet

Added Antima Comet, which was missing.
Add British spelling for 'Defense Grid'

Added the British spelling of 'Defense Grid' ('Defence Grid') as an
alias.
Merge pull request #2 from just-a-bird/master

Add Odin, Antima Comet, and several aliases