Added Search Result Picker window
Added FilmLookup dialog demo project
Implemented Result picker button commands
Factored out caching from FilmLookupService
Split film into CachedFilm, GuiFilm and Film
Film uses IResultPicker, e.g. GuiFilm uses GuiResultsPicker
Made MediaCollection generic so it can be used to build any type of IFilm.
Demo uses CachedFilm with its FirstResultPicker instead of hardcoded IDs.
GuiFilm implements INotifyPropertyChanged and uses Dispatcher to run lookups.
Caught some errors and managed some nulls.
Added query text to LookupPicker gui.
Required new LookupContext class so it could be easily passed with results.
Picker demo asks local/http.