Add flags to starting_location class.
Let the starting_location prepare the map.

This moves the t_window_domestic to t_curtains translation into the starting_location class. More can be added there.

Also search for the first house with the starting locations target, not the ident of it.
Add boarding up the starting house

Boarding up changes doors/windows to their boarded counterpart
Gives the player a hammer and a screwdriver
Moves furniture in front of doors/windows
Allow starting outside of any building.

Added flag to starting location to bypass the is-outside flag when placing the character.
Move the z-parameter into the center point parameter of overmapbuffer::reveal

It makes no sense to put that z component separate.
Move choosing the starting overmap coordinates into starting_location.

Changed overmap::first_house to overmap::find_random_omt because it is not specific to houses anymore.
Also changed it to look on all z-levels.

Moved some code from game::start_game into start_location::setup to setup the overmap coordinates (and levx, levy, levz)
Moving placing the player in the reality bubble into the starting_location class.

This is more a task of the starting_location and can be extended there.