Enhance measurement system support in routing manager.

It is useful to be able to set the measurement system independently of
the locale used by the routing manager. Add accessor functions for the
measurement system to the routing manager classes.

Locale and measurement system properties are also added to the
RouteModel QML type.

Change-Id: I8ee9fbdb5ab94615fef7019914b0f104aebfa9c8
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>
Remove RouteModel::locale property.

I missed that the functionality was already available in Plugin. The
measurementSystem property is retained.

Change-Id: Id65aa29cb7078d3be7310081278a032edc25bf0d
Emit updateTimeout() when regular position updates aren't received.

The documentation indicates that the updateTimeout() signal should be
emitted once when the source determines that regular updates will no
longer be received.

[ChangeLog][QtPositioning][Geoclue] The Geoclue position source now
emits the updateTimeout() signal when position updates do not arrive in
a timely manner.

Change-Id: I87c31a60a8e718a0ab72a1e270a93e967307f77a
Send requested update interval to Geoclue providers.

Send the requested update interval to the active Geoclue provider. The
update interval is sent by passing and 'UpdateInterval' option to the
provider. Not all Geoclue providers support this setting, in which case
they will report position changes at their default rate.

The Geoclue position info source no longer limits the rate of position
updates internally.

[ChangeLog][QtPositioning][Geoclue] The Geoclue position info source
provider no longer internally filters position updates to the
requested update interval.

Change-Id: I96a112575173d4fa485905b1885a98fe43da1153