Adds a new design-time font property for when `&displayMap` is in use in
a keyboard, so that the web debugger can use that font as appropriate.
If the keyboard does not have a `&displayMap` store, then the DisplayMap
font property is disabled, and the web debugger will use the OSK Font
instead, as previously was the case.
Note that the font for `&displayMap` has to be installed on the keyboard
author's system in order for it to be served up.
Fixes: #12123
Fixes#9541.
Also adds version 16.0 support to the kmcmplib compiler constants, and
unit tests for both versions. Does not add any support for automatic
version feature detection, because that forces an inverted dependency on
the touch layout compilation phase (done in kmc-kmw), which would be a
significant refactor. This may be something we need to support in the
future.
Part of #7045.
Indicates that the .kmx file has additional header structure immediately
following the COMP_KEYBOARD header. Used by KMXPlus file format for
supporting LDML keyboards. Requires VERSION_160 or higher in keyboard
file.
