Fix gstreamer crash when meta-data is of incorrect type.

GStreamer tags are typed and the correct type must be used when inserting
a value into a GstTagList or subsequent merges or data accesses can crash
because of invalid casts.

Found while adding additional mappings for GPS values.

Change-Id: I95ab40a480a4685bf4e69064315557faa9de288e
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>
Add meta-data mappings for GPS and camera make and model to camerabin.

This enables writing gps positioning information to captured images.

Change-Id: I663f7b94b5e6040865358df1ae45d67b73c54f92
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>