Fix searchs for insert positions in QDeclarativeListCompositor.

Fix searchs for insert positions in QDeclarativeListCompositor.

When scanning for a start range don't stop on ranges that don't
have an group flags unless that range is the terminal range.
This fixes a couple of issues where moving an item to the end
of the list would position it after a prepend only range instead
of before it, or would miscalculate the iterator offset resulting
in invalid indexes in the insert range.

Change-Id: Ic4aa001edf43ec86a65d432cd8f80abf0b44d276
Reviewed-by: Martin Jones <martin.jones@nokia.com>