Changeset fdea415 in git

src/: Hook up GPX export options to export entrances, fixed points,
and/or exported points, and specify coloured pin symbols for these
types of stations. These options now default to what's being shown
in the survey view, like other export options. GPX export
"creator" how includes the Survex version and website URL, and the
survey title is includes as a <name> tag inside the <gpx> tag.