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

Merge pull request #32 from Rutherther/combat

Add combat extension

fix(packets): Add new unknown field to ski packet, make rank of SkiSubPacket optional

fix(packets): make skill effect in SuPacket nullable

fix(packets): make su skill effect nullable

fix(packets): make correct fields in drop packet

fix(packets): make st packet buff vnums a read only list instead of list

fix(packets): make cancel unknown nullable

fix(packets): make cinfo icon short

fix(packets): make eq packet size optional

feat(packets): add cancel packet

feat(packets): make position in su packet short

fix(packets): make correct types in gp packet

fix(packets): make correct inner separator in eq sub packet