NavControllerBase is the core of ionic 2 navigation. It handles all the transitions and it is complicated code to follow.
I am refactoring it to allow future developers and contributors to follow it better.
!node.parent now becomes node.isRoot()
ViewController does not remove itself from the stack, but two new auxiliar function in nav controller: _insertView() and _removeView() are used to add a view to the stack.
And so on...
All e2e and unit tests passing...
For some reason, apparently related to the NavOptions.ev field,
this deep copy was turning into an infinite loop on a Nexus 7 / android 5.1.1 webview.
Replace with a non-deep copy since the deep copy is unnecessary in this case.
