Add support for XEFIS_MODE and <if>s in config.
Fix raising runway to work as in docs.
Better naming of vars in HSI instrument.
Change io/mouse to use <settings> instead of own XML syntax.
Docs update.
Fix creating multiple properties under the same path.
Fix HSI: center-on-track.
Fix displaying pointers on loc/gs ladders.
New (mixed) configuration for FG and real hardware.

FG enabled with XEFIS_MODE=fg environment variable.