Simpler and better use of time display for tracks.

Make consistent use of time format as used in trackpoint and waypoint displays.
Ensure string is long enough for potential dates.

I don't know if any locales have longish formats, but it won't do any harm to be able to show them fully.
Make window related values available on acquire initialisation.

Primarily to enable getting the viewport, but without going through the add_setup_widgets stage.
Thus it enables an acquire method to start without further user input.
Prepare for dynamic VikDataSourceInterface creation/deletion.

Allow passing in of data into the acquire method.
Enable a function callback on completion of the acquire method,
 thus can free the allocated memory of the VikDataSourceInterface itself.
Make mpp_to_zoom() a generic function

It doesn't rely on any Webtool center data.
[DOC] Ids are not necessary in these configuration files.
[DOC] Promote Extending Viking to the top level section in the manual.
Rework mpp_to_zoom() to return the actual zoom level and handle all Viking zoom levels.

This now allows 'OSM (Edit)' to work up to the maximum zoomed in level.
Add a new webtool datasource to allow acquiring data from URLs that return a file.

Adds a built in OpenStreetBugs extension.

Allows defining your own datasource references via a datasources.xml file,
 similar to the external_tools.xml methods.

The URL format reference encodes how the location (and zoom) parameters are substituted.
The file type returned should be specified and is passed on for the -i parameter for GPSBabel.
[DOC] Explain datasources.xml usage.

Add an example datasources.xml file.
Add support for acquiring OpenStreetMap Notes as GPX files.
Merge branch 'DatasourceRemoteFile'