Moved flexible box model attrs out of Container and Modal js
into a common function
Added custom selector logic to modal view
Enable basic node attributes
Dont send add and remove class calls if no comm exists
Added tweet watch example
Updated View list in example notebook (+ModalView)
Fixed timecode for python 2.x
Fixed modal centering code
Do not vertically center modal
Replace model 'update' event with the backbone 'sync' event, added in 1.0
Added Factorization example
Added Widget Tester example
Added support for disabled flag to button widget.
Make selector property of the add and remove class packets optional.
Added `method` property to messages from the front-end
Basic test widget button.
Added button tests
Cleaned up utilities in widget casper js tests
Make widget tests use new casper util functions
Added basic bool widget tests