* refactoring
* allow for creation of games as spectator
allow setting the amount of games per user to none
remove limit on amount of games when creating a game as judge as
spectator
* refactor common/server_player.cpp
* do not close games with spectating host automatically
* remove check that filters out 0 player games
this check didn't really do anything, deleted games are removed before
it would be reached
* don't transfer host to spectators
this seems to cause a bug, also present on master
That marker is only recognized by pb3-compatible compilers, meaning that
tools which are otherwise compatible with our files break on them.
Notably, this includes hprotoc (for haskell).
