Make geo coordinates animatable in QML.

Interpolation logic in AnimatableCoordinate has been moved around so
that QGeoCoordinates can be animated directly by QPropertyAnimation.

A new QML type has been added, 'CoordinateAnimation', for animating
coordinates in QML. This type follows
the pattern of 'ColorAnimation' and other specializations of
'PropertyAnimation'.

QDoubleVector2D, QDoubleVector3D and QGeoProjection has been moved to QtPositioning

Testcase for CoordinateAnimation has been added to declarative_ui.

AnimatableCoordinate and QGeoCoordinateInterpolator are redundant
and have been removed.

Change-Id: I0809da566e1800274384f9c5337df65623d1e61a
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>