3 col transitions

...e third column

Hi Roman,

In preparation for the visualization and other widgets being shown in the middle of the results page, I improved the expanding column interaction on the results page in a few ways:
* made 3rd col collapse into first col when screen is tablet sized
* added a model to keep track of which columns are open and which are closed
* now there is a method for the page manager to call to make the center column full width or return it to default size.

I did two things that you might not like : the page manager 3 column view is listening to the window resize event--I think I should change this to a single app listener on window events that other widgets can subscribe to.
I also had the problem that right now the "show" event is being triggered on page layouts before they are actually in the dom, so for now I re-triggered the event in the master page manager's "onSelectedChange" function. I also added a "detach" event.
Not here, if you need, it should be part of the show call inside the child. But is it really needed? If only for some widgets, then only they need it