Add "ahrs-selector" and "aoa" modules.
Handle --copyright options.
Rename main.cc to xefis.cc.
Add Current and Weight types/properties.
Add stall warning flag to systems/aoa.
Ensure that modules are not deleted by QWidget on exception in ctor.
Make PropertyNode noncopyable.
Reorder component initialization.
Add (refactor) GenericProperty::stringify (format, ...).
Make InstrumentAids methods public, and change inheritance to protected.
Update instruments/status.

Change 'critical' to 'warning'. And thus have cautions and warnings.
Change property names to have 'input.' and 'output.' prefixes.
Add master caution/warning buttons support.
Let DeltaDecoder use copy of Property, not reference.

It's safer.
Fix a couple of warnings made by clang++.
Add red/white/blue led icons.
Stop sounds upon destruction.
Add the helpers/sound module.

Remove sound support from instruments/status.h.
Set LC_ALL to C.