Feedback

Suggestion for visualizing feedback loops while connecting (a feedback loop is created by holding shift and starting to drag from an output port away)
![feedbackloop-conneting](https://f.cloud.github.com/assets/49342/636452/5d2954f4-d283-11e2-84ab-dcef33d17c71.png)

And for visualizing established feedback loops:
![feedbackloop-connected](https://f.cloud.github.com/assets/49342/636457/93bbbc5a-d283-11e2-9353-738fb9107864.png)