feat(packets): update packets to not use nullable if not needed

Merge pull request #45 from Rutherther/feat/mates

Add support for mates

fix(packets): correctly represent finfo

feat(packets): add nullable wrapper to represent a compoud type that may be null as a whole

chore(game): add missing documentation

feat(game): add mates processing

feat(game): add revive handling

fix(packets): finfo contains just one update

feat(packets): add party stat packet

feat(packets): add pet and partner skill packets

feat(packets): add pclear packet

feat(packets): fix pinit packet for various entity types

feat(packets): add inventory packets

feat(packets): add many new packets

chore(packets): add documentation for ski packet

fix(packets): make generator work with packets that have 0 members

fix(packets): make bs packet effect id nullable

feat(packets): make skill vnum in su packet nullable

fix(packets): add header for st sub packet

feat(packets): add support for st buff vnums with levels