[Feature] Bing Search Media Picker.

__Code Review:__ http://mrccodereview.cloudapp.net/ui#review:id=2316

__From @MichaelKalygin:__

1. Imporved Media Pickers factory.
2. Improved MediaList control.
3. Implemented form for mediapickers.
4. Implemented Bing Search mediapicker.

__From @alex-zen:__

1. Created sample page where Bing search results displayed (images, videos, documents - only pdf).
2. Replaced Bing search response types with default types from BingSearchContainer.cs