IB/Factory.cpp: rename "Height GPS/AGL" to "Altitude GPS/AGL"

We use "Altitude" consistently throughtout the product
Descriptor.cpp: if nook, don't open internal sensor

This avoids a crash on startup b/c nook has no
internal sensors
InputEvents: add IsVisible()

Allows caller to determine if menu is visible or not
GlueMapwindow: clear menu when map items list displays

If a menu is visible, clicking on the map simply hides
the menu.  Pan menu is the exception.
dlgPlanes.cpp: fix list font color

It was not using the correct font color for focused
and selected list items