audio canvas and description canvas get disabled when playing video

removed uneeded file LiveDescribe/Model/Video.cs
description gets selected in list when it is playing

added new event in mainwindowviewmodel OnPlayingDescription
Change Project.GenerateDescriptionFile behavior

Now returns a ProjectFile instance.
Merge branch 'master' into danieldev

Conflicts:
	LiveDescribe/LiveDescribe/ViewModel/MainWindowViewModel.cs
Refactor InfoTabViewModel

Hopefully makes selecting a Description/Space less confusing.
deletes unused description files when closing a project
Dynamically Update SelectedItem's Text

Also refactor DescriptionInfoTabViewModel class
Enable or disable Textbox based on var being set

The var being SelectedItem
Merge branch 'valdev'

Conflicts:
	LiveDescribe/LiveDescribe/LiveDescribe.csproj