sourceid handling: use only first token

Rest of the source id is usually a descriptive comment.
bbbikeleaflet: dynamic copyright year
bbbikeleaflet: new cgi parameter osmdemap

If set, then the German OSM map from openstreetmap.de is used, not the
default style. This has the following effect:

* slower loads, because the {a,b,c} scheme is not used here
* longer Expires durations (up to three days), so better suitable for
  offline mode
* "German" map style
GPS upload: allow route name "0"
bbbikeleaflet css improvements for bottom controls

* attribution layer is now _below_ the LOC/CLR controls
* attribution layer text is right aligned
bbbikeleaflet: trim digits also for accuracy and altitudeAccuracy

This is done with the new helper function _trimDigits.
srt-style: tourism=information now rendered with information symbol

Previously it was rendered with the toilet symbol. Unverified change.
partially reverted commit 9571d58783a9517438a8bc3bced95f56daf59ac5

The change regarding the "Pref" subelement was reverted, because the
change broke the iOS app, which was insisting on the Pref value being
a string, not an integer.
data update