Activity diagram: Reconnection of object flow source #610

With the reconnect "tool", it is possible to select an object flow tsource and to reconnect it to an input pin.

Test steps:
In an activity, create two opaque action which have an input pin and an output pin.
Create an object flow between the output pin of an opaque action and the input pin of the other opaque action
Select the source side and reconnect it to the input pin

With the Object Flow creation tool it is not possible to create an objet flow from an input pin.