CBN creation inside boundary fix

1.  Fix for issue http://adsk-oss.myjetbrains.com/youtrack/issue/MAGN-784 - An undo action gp shouldnt be created during load.

2.  Added delete and recreate connectors for input ports of CBN to make them undoable
     http://adsk-oss.myjetbrains.com/youtrack/issue/MAGN-775

3.  CBN size back to previous way.

4. Added test case for MAGN 411