0.7.0

Added

• getStartPosition method to define from what number start counting models
• shiftWithTimestamps method to update timestamps when shifting models
• Experimental lockPositions method to disable database queries during insertions

Changed

• Now timestamps will be preserved by default when shifting model positions
• Method newPositionQuery now is public
• Use SQL count method instead of max for calculating position at the end
• Refactored using PositionObserver