Draw2D touch version 5.6.8 (TEST) released

+ fixing method Line.setEndY. The broken implementation swaps end/start coordinate.
+ enable selection of connections within Composites
+ fix broken drag/drop of lines. Line didn'T update end/start after drag&drop end points
+ add the start/end point of a draw2d.shape.basic.Line to the JSON document. Lines can now read/write to JSON too.
+ extend constructor of ShowGridPolicy that the policy can listen to the "zoom" event of the canvas and apply them to the grid size.
+ support Layout.clone()
+ fix grouping error of connections with a label as a child. Label pushed into the background after grouping