Fix GPX symbol names for Garmin Oregon 450

While testing the GPS export using Garmin Oregon 450 with software
version 4.20, it was noticed that no symbol seemed to be recognized by
the waypoint manager. The problem seems to be that this device
differenciate between lower and upper chars in the symbol names.

Casing of all symbols apart from 'custom placeholder' were modified into
'Title Case'. The hash helper functions had to be changed to ignore the
difference between lower and upper cases. The import had to be extended
to convert lower case names in sym to the version in the table to work
correctly.

Reported-by: Frank Eckelmann <f.eckelmann@gmx.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Maintain waypoint symbol .vik file compatibility with older Viking releases.

Older releases of Viking will only recognise waypoint symbols in lower case.
Fix incorrect GPSBabel/Garmin symbol names.
Amend ground transport icon colour to differentiate between it and the school symbol.
Add 'exit' waypoint symbol.

Icon is taken from the public domain OpenStreetMap classic icon set.
[NB these exit symbol edited to make the white background transparent]
Add 'helipad' waypoint symbol.

Icon is taken from the public domain OpenStreetMap classic icons set.
Add an example viking file with all the supported waypoint symbols in use.
Add preference to support writing Waypoint symbol names in Title or lower case.
Maintain support of old waypoint symbol names with new hashed lookup method.
Merge branch 'WaypointSymbolImprovements'
Fix showing map timestamps on Windows on the map tile info dialog.

For some reason it would always show '(null)', so rewrite in glib functions.
SF#3608411: Part 2 - Avoid creating command window on Viking start-up.

Ensure Viking is compiled as a 'Windows' application.
Otherwise it defaults to being a console program.