[update] Report direction and vertical speed with Geoclue plugin.

Geoclude provides both direction and vertical speed information with
the velocity interface. These values were previously being ignored.

[ChangeLog][QtPositioning][Geoclue] The Geoclue plugin now reports
direction of travel and vertical speed attributes, if supported by the
active Geoclue provider.

Task-number: QTBUG-36298
Change-Id: I9f99a64f3c2bd78a06a6c60e0ef3af6f75223e9f
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>
[update] Attempt to fix crash in tile cache.

The tile cache can sometimes end up with null pointers which causes a
crash when saving the state of the cache queues to disk. Fixed by
skipping over these entries.

Task-number: QTBUG-36486
Change-Id: Ifa359bd1f9dbe37da0d5b208a7c4ee7a26f8bd44
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>
Merge pull request #25 from amccarthy/master

Cherry pick fixes from upstream