exponential decay, tolerance times
Merge branch 'get-gebaeude_t' into eta-etd
CODE: forward-port bridge building code from standard
CHANGE: build low bridges by default, allow "trench bridges" without a
ramp or between elevated ways
Merge remote-tracking branch 'refs/remotes/jamespetts/way-improvements' into james-low-bridges

Conflicts:
	bauer/brueckenbauer.cc
FIX: merge some things
forward-port some more of the way height clearance code
oops, this wasn't meant to go on a branch
CHANGE: build high bridges by default, low bridges with Ctrl pressed
FIX: reinstate the test for high buildings that we shouldn't build
bridges over
rm duplicate code; build connecting roads properly
FIX: be consistent when building two-tile bridges (which don't make sense)
FIX: higher maximum cost for roads connecting to our newly-built bridge
minor fixes
FIX: removing a one/two-tile bridge shouldn't leave half-connected roads
fix removal of ramp-less "trench" bridges
build low bridges by default and high bridges when ctrl is pressed
rather than the other way around
FIX: extend elevated roads when building bridges from them
print more statistics
hack to share timing information between convoys on the same line, at
the same point in their schedules, and composed of the same vehicles.