remove map::traps vector and use g->traps instead
add constant access to field iterator
add some actions to shift the view vertically
add some terrain types for z-leves above 0
make critter position functions const

add Creature::pos, returning a tripoint
implement them for monster, npc, player
change creature_tracker to use tripoints
make wrapper for rl_dist that take tripoint and point
make map::drawsq and map::draw expect a tripoint as center
replace INBOUNDS macro with inbounds function

make inbounds const, add wrapper for tripoint
move call to map::build_map_cache outside of game::draw_ter

Instead of calling it (which will take a long time with z-levels) from draw_ter, call it before calling draw_ter.

In some places a call to build_map_cache is not needed at all!
extend tripoint to be json compatible
remove the monsters-on-stairs system, not needed for z-levels
add min-z, max-z members to map, default to currently (0,0)

make the nul* members of map mutable so they can be accessed from const methods

added some helper function for getting the nonant in map

made the tinymap simpler and made map non-virtual
make map::loadn recursive instead of relying on the caller to call it again
made loadn & saven expect two tripoints: world coords and grid coords
allow overmap to generate overmap terrain "air"
convert some code to use map::get_nonant

add missing definition of map::valid_gp
duplicate many functions of map, to accept tripoints as paramters instead of x,y
make some methods in map const
make map::move_cost, map::trans, map::has_flag use tripoints as parameter and properly refer to vehicles

minor changes for more const methods

bugfix in map::has_flag_ter_and_furn
create game::draw_critter to draw any kind of critter at once
create submap containing air and roof tiles,

contains special handling to place roof on top of indoors tiles and stairs on top of stairs

make the starting shelter have a upwards stair to reach the roof