fix editmap derp
add function for selecting the possible list of targets and autoselecting the previously selected one.

makes game::last_target an int, as it is essentially an index
remove game::z_at, not used anywhere
nail shortcuts description!
Merge branch 'another_fix_for_mod_menu' of https://github.com/illi-kun/Cataclysm-DDA into illi-kun-another_fix_for_mod_menu
Merge branch 'targetting' of https://github.com/BevapDin/Cataclysm-DDA into BevapDin-targetting
Nerfs Hydraulic Muscles

As requested in #6024.

Active muscles now emit 19 noise each turn (between bubblewrap and a car
horn) and cost two power every three turns.  (Twice as much as before.)

In practice, the Bionic Patient can power up to win a fight or schlep
something, but that's it.
Merge pull request #6027 from KA101/HMnerf

Nerfs Hydraulic Muscles
Merge a map edit fix.