Version Aug 25th
Version Aug 25th

1.  Realized cycle detection.
In cycle01.json, there is one circle(c6, c7, c8), the force-layout works
well for this situation.
I will test more examples in the next few days.
2. The label's padding is added.

My next step is fix the collision detection of labels.

usc-isi-i2/karma-model-layout,usc-isi-i2/karma-model-layout