Moar guilds

As the hot weather Italy is experiencing these days kills me, I can't
guarantee everything works. Things I tested and debugged:
- Guild Chronicle (view -  implemented edit but not sure if it works)
- Guild Board (view/edit)
- Guild Creation
- Guild Inviting and Joining
- Guild Renouncing
- Guild Hall (partially: entering breaks the guild chat somehow, only
level 3)
- Guild Chat (partially)
and probably some more things that I don't remember.
Also, wtf, 11 days since last commit? I'm mad.