This patch enables multiple MetarProperties instances tied to the
property tree. For each node's value of /environment/realwx/metar
one MetarProperties instance is created and tied to the property
tree named there. (See FGDATA/Environment/environment.xml for details)
At least one instance will be created to provice backward compatibility
to the existing live-data weather system. This instance (tied to
/environment/metar) fetches a METAR for the nearest airport at a regular
schedule. All other instances fetch a report for airports named in the
property station-id. It re-reads the report every 15 minutes, the
remaining time until the next fetch will be scheduled is in the property
time-to-live. This property can be written to, to extend the live of
this report or schedule an immediate reload by setting it's value to zero.
This patch also provides magnetic variation for the station's location.
Revert to using inches globally by default, unless the user sets the
property /sim/atc/use-millibars. Whilst this is therefore wrong by
default, it is probably the best thing in the short term since
FlightGear's altimeter dialog and the altimeters on the default
aircraft set using inches.
Primarily an improvment to the internationalisation. Previously the ATIS considered
the world as either the UK or the rest of the world. Now it considers it as US+Canada
or the rest of the world. This is much more consistent with global usage of pressure
units as either inches or millibars, which is the most important difference. Also
some other tweaks and cleanups.
The apt.dat file contains inconsistent case for many airport name abbreviations,
e.g. MUNI/Muni and intl/Intl. Evaluate the abbreviations in lower-case when
expanding them in order to avoid missing any.
Some fixes, and refactoring of the lexicon and abbreviation remapping
into headers where it can be picked up by the scripts that generate
the voice files.
