This is similar to the PATX chunk.
Minor refactoring to enable some code sharing between two chunks.
Fix MakeSettingsPatxList always regenerating cache.
Update documentation of PATX chunk structure.
Probability of placing an arctic tree is now an exponential decay
function of height distance from the snow line, instead of the previous
50% blocks.
This results in a more gradual thinning out of arctic trees in
each direction.
The algorithm is: p = exp(-3 * distance / range_setting),
using a rather crude approximation of the exponential function.
The no_trees_on_this_level setting is not really useful, and its
dual behaviour to disallow discrete height levels and turn on the
snow line behaviour is unintuitive.
Replace it with a simple on/off setting.
These correspond to versions from v2.1.108 and v2.1.147.
The oil rig airport type bug is fixed as of version 221.
The oil rig type has been moved, but this is not a problem as
the afterload code already remaps it to the correct value.
The cost scaling issue also seems to have been mostly fixed
as of version 221.
This is useful for loading settings from legacy/special versions,
where the corresponding setting is somewhere else and/or a PATX setting,
with duplicating all the info.
Use this to load SpringPP settings which have a corresponding setting.
No longer set vehicle lateness to 0 if separation fails, instead
leave it as it was.
The setting defaults to 100% (full abruptness, old behaviour).
Reduce the setting if auto separation is too disruptive, e.g. causes
excessive waiting in stations.
Note that this is not savegame compatible.
This is an exponentially weighted moving average of occupancies updated
when any vehicle in the shared order set leaves the station of that order.
The weighting factor is an adv setting.
Savegame version 220
Bin all extra settings added in SpringPP.
Bin extra features: trip histories, more conditional orders/jump counter,
prev order time, snow-line chunk, town auto adv. campaign, etc.
Fix vehicle flags.
Fix bridges wrt height changes.
Handle 60-bit RIFF chunk sizes.
Doesn't deal with huge airports, loading games with these may
lead to undefined ehaviour.
PAX signals and traffic lights are ignored.
