Add party interface, #25
Implement parties in character plugin, #25
Split exp across parties, #25
Add party support to combat, #25
Prevent members of the same party attacking one another,  #25
Add party compatibility into skills, closes #25
Actually register party command correctly
Fix invite removal
Create parties in party directory
Prevent giving double experience
End fights on party wins
Allow fight wins if not all party members are still alive
Prevent starting fights if all members are from the same party
Merge branch 'feature/parties' into develop