add flow charts
add nodes and start drwing graph for eventbus
extend API, fix glitches
create a mafQt class for redrawing
refactor at high level the design of the plugin
refactor putting the generic classes in mafGUI
continuing refactor
clean code for widget connectors
Merge branch 'charts'

* charts:
  clean code for widget connectors
  continuing refactor
  refactor putting the generic classes in mafGUI
  refactor at high level the design of the plugin
  create a mafQt class for redrawing
  extend API, fix glitches
  add nodes and start drwing graph for eventbus
  add flow charts