Change trap detection dynamics.

Traps now must be searched for. Candidate search radius increased to 11 squares.

Detection is combination of perception, tiredness, stimulus, luck, distance from trap, and trap visibility.

Traps must be detected before being known and seen.

Numbers probably need to be tweaked, but in my tests this seems fun despite my earlier (and overblown) apprehension.
redundant is redundantly redundant.
Removing dead code.

Not sure if map_extra_chance was kept for reference, but it's dead Jim.
Trap search done on move.
insert some comment about juggalos, science, magnets, and magic.

Oh, and maths. Search math should actually search an area of 11.

And more comments for the why the math is the way it is in search_surroundings().
Merge remote-tracking branch 'upstream/master' into its_a_trap
Turned off stashes/extras... i think.
Remove my ignorant comments, turn of just "stashes" not all the extras.

After fiddling with the numbers and trying out some calculations, I kept the weighted numbers as is and if stash was chosen, it acts as if no extra is chosen and falls through. This keeps all other extras appearing at the same quantity and frequency as they would appear now.
Merge remote-tracking branch 'upstream/master' into its_a_trap
Remove errant comment.
Merge remote-tracking branch 'upstream/master' into its_a_trap
Check for trap visibility when highlighting possible interaction squares
Fix geiger counter: report radiation level on item position.

Bonus: fix some warnings about signed vs unsigned in iuse.cpp
Add a string to be translated.
Remove excessive semicolon.
Merge branch 'fix-geiger' of https://github.com/BevapDin/Cataclysm-DDA into merge
Merge branch 'its_a_trap' of https://github.com/jeremyosborne/Cataclysm-DDA into merge