Bug 837678 - [cost control] Implement new startup loading events

When the App is loaded at the first time, shows to the user the first step of the FTE. The HTML code of the fte is loaded on an iframe that is hidden until the fte_ready event is fired. I emit this events here because it is when the App make visible the iframe (line 74). 
Until the user configure the usage App through the fte, the App doesn't make things in background