APPWTV-28 events

First embrionic implementation of event handling:

1) I had to move connectUI in app.js for the sake of quicker testing, I cannot exclude it would work into ui.js too  

2) As I could not bind keyboard arrows, navigation is performed using ASDW + Enter. Those keys are bound to an object that manages navigation in the BrowserView.  
First of all, open console (webinos should trigger this) and call **webinosTV.app.connect()**  
Then (having focus on the window) **press enter** (to enable navigation), then D or A (without shift) to move among the columns. The column is highlighted by adding/removing a new SASS/CSS class ("nav-selected", an orange border obtained by complementing the blue)  

3) Still to be implemented: 
* up/down navigation using DataView selection methods; 
* stop navigation using spacebar and related callbacks.