emit event when mimetype are append to output area.
fix Brian and Min comment
Fixme comment + whatsnew
reorder class properties
put OutputArea map at the end
Added ability to pack and unpack arrays.
Added test for pack and unpack Model functions
Added debug log to see what is happening...
Added support for RuntimeArray
Merge pull request #5023 from jdfreder/widget-arrays

Widgets- add ability to pack and unpack arrays on JS side.
Merge pull request #4774 from Carreau/emit-output

emit event on appended element on dom
Adding interact.py.
Adding Interact and Lorenz examples.
Updating interact to new APIs.
Updating interact to work with latest state of widgets.
Adding .widget to function.
Get widgets from function annotations and default arguments.

Also, preserve the order of function parameters from the signature where
possible.

This uses a backport of the Python 3.3 signature machinery that @minrk
found and improved.
Renaming interact.py->interaction.py to improve imports.
Fixing interact imports.
Utter interact insanity.

This involves a bunch of really complicated logic to handle the
different ways that function parameters can be processed in Python.
Most importantly, this includes support for *args in interact.