Doc: add docs for Calqlatr example

Describe the QML and Qt Quick features that the
example illustrates.

Change-Id: I9a3656873ac1a5a8cdf31b1f85528b1bf081df79
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>
QWindowsFontEnginge uses GetGlyphOutline which seems to fail

for fonts containing embedded bitmaps.

Change-Id: I035df24d16f1c9707fff54b0920c8139fda3ddec
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>