remove AdaptiveCellEdge.findOneBisectionObstrutor()

  - modify QuadrangleAdaptiveCell accordingly
Fixed the bug of QuadrangleCellDemoDrawer that vertical edge opposite marks have wrong direction
Let AdaptiveCellEdge be able to have more than 2 opposites

  - also add addOpposite(AdaptiveCellEdge)
in QuadrangleCellDemoDrawer, enlarge the opposite marks size and add a switch of wheather show opposite marks.
let QuadrangleAdaptiveCellFactoryDemo only fire cell fission when button1 is clicked. And other improvement:

  - add a checkbox to switch opposite mark display
  - remove strange debug checkbox