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
delete unused description files when closing project
Dynamically Update SelectedItem's Text

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

The var being SelectedItem
added preprocessor commands to get rid of support for extended description

created new configuration called ZAGGA that has the zagga conditional
variable set
Merge branch 'valdev'

Conflicts:
	LiveDescribe/LiveDescribe/LiveDescribe.csproj
Merge branch 'master' of github.com:IMDC/LiveDescribe-Desktop
got rid of rewind and fastforward buttons