change saved_game & savefile format

The main intentions of this patch are:
1) To remove redundant information in savefiles
2) To fix mp/sp bugs: "modification [event]s wont be reaplied if one advances from a mp game (also if it was reloaded from sp that was reloaded in sp)"
3) To fix "start-of-scenario mp saves are broken"
4) Clear up playcampaign.cpp s code

This patch changes the wesnothd server protocoll causing incompability with oder version regarding networked mutiplayer 

Also between some commits in this pr some mp related things will not work.