make wesnothd use savefile format for new games

This patch changes the mp wesnothd protocol.

multiplayer connect now works as following:
multiplayer_create/configure creates saved_game object which is then
loaded by mp_connect and sended to the server in the usual savefile
format, this especially implies that [side] are no longer at toplevel
but instead nested into [scenario] or [snapshot].

mp options are saved into state (the saved_game object)
(state_.mp_settings()) previously we had a separate mp_settings object
for that now we only have one mp_setting object.

This commit still not fixes mp modification/era events/options. The
reason is, that i want to move the expansion of those to saved_game.cpp
for better compatibility to Sp (Especially make era events work in mp games
reloaded in sp), but if that won't work i'll just enable them how they
were before.

There  are still some things to do. Especially the server generated
replay-saves will be completely broken. (will fix in another commit)

we don't use the [replay_start] as starting pos in mp anymore so i removed
2 lines in playcampaign that assumed that.

I also removed soem code in mo_game_utils that seemed redundant, bugged or useless

since we now send the [carryover_sides_start] over the network too there
is no reason to apply [carryover_sides_start] before getting into
mp_connect engine (when advanging the the next scenario), even more,
since the new code expects only ONE of [carryover_sides_start] or
[carryover_sides] to be present, we cannot expand carryover_sides_start
in playcampaign before going to mp_connect because we might wan to modify
[carryover_sides_start] in mp_connect

still TODO:
* rename mp::configure::get_parameters
* reimplement mp modification/era s events/options
* remove fields from the mp_game_settings object
* remove disabled/outcommented code
make wesnothd use savefile format for new games

the serverside part
fix test/ compilation
fix servergenerated replays

I also removed 'mp_game_title' because if i leave it, it casues an 'attributes not in order' error since level_ contains attributes. Idk what it does so i removed it. if we want it we should write in into level_
add valid() function in saved_game class

and add comments about other functions.
fix commandline mp start
ignore allow_new_game for reloaded games

this fixes a bug when reloaded games  started immideately for joining
players.
expand save_id default value eralier

Set this default value immideately after reading the scenario is
importent because otherwise we might endup settings this value to the
multiplayer players name, which would break carryover. (doing this in at
config loading in game_config would be ok too i think.)
fix mp reloading

having with network/network_ai together with force_lock_settings_ cause
assertion errors because update_controller_options won't add any
possible options.

this patch restores the previous behaviour where force_lock_settings_
was ignored for reloaded games.
fix [option]s/[events]s in [modification]s and [era]

this was broken by a commite earlier by me.

We now add them to teh scenario in saved_game.cpp and not in the mp
code. The reason is that we stil want them to work if a mp campaign game
was reloaded in sp.
remove mp_game_settings::scenario_data

this is not used anore since we use saved_game::starting_pos now