auto node creation code added for student mode
Merge branch 'master' into pradeep
Comments on autocreation work in progress:
Used different method of hooking to drawModel.addNode(); see
  colorNodeBorder().
Maybe updateNodeLabel() should be in draw-model since this
  has to do with the drawing canvas?
See comments in autocreateNodes()
auto creation after code review - tested student mode
automatic node creation for author mode
Add css style sheet for checkboxes, sliders, and the select widget.
This makes the checkbox widget work.  Use widget for all checkboxes,
using the same style handlers throughout.
Merge branch 'master' into pradeep
Add some comments about sending new nodes to PM and
removing if(...) in autoCreateNodes.  Fix whitespace.
Fixed bug in AUTHOR mode where zero initial value was
not handled properly.  Also, zero initial value was not
displayed.
fixed copyright licenses
fixed minor bug in node labels
Merge branch 'master' into jingxian2