Play video from folder

[peteruithoven]

It's quite common that video torrents are folders with the video file. I'm trying to make it easier to play that video from Torrential without having to deal with files.
Fixes: #107

An alternative approach might be to have an easier / quicker way to open a specific file in a folder, for example by showing the file tree in a menu somewhere.

ToDo:

• Determine if torrent is playable
• Add play video option to context menu
• Open video in default video application

[peteruithoven]

Looking through the AppInfo API I noticed there is a launch_default_for_uri function which seems like a much easier way to do things. It removes the need for the content type guess and the need to create a uri list for example.

Before

private bool open_file (string file_path) {
    bool certain = false;
    var content_type = ContentType.guess (file_path, null, out certain);
    var appinfo = AppInfo.get_default_for_type (content_type, true);
    if (appinfo != null) {
        var file = File.new_for_path (file_path);
        if (file.query_exists ()) {
            var file_list = new List<string> ();
            file_list.append (file.get_uri ());
            try {
                appinfo.launch_uris (file_list, null);
                return true;
            } catch (Error e) {
                warning ("Unable to launch default handler for %s", content_type);
            }
        }
    }
    return false;
}

After

private bool open_file (string file_path) {
    var file = File.new_for_path (file_path);
    if (file.query_exists ()) {
        try {
            AppInfo.launch_default_for_uri (file.get_uri (), null);
            return true;
        } catch (Error e) {
            warning ("Unable to launch default handler for %s", file_path);
        }
    }
    return false;
}

Should I simplify the open_file method or am I missing something that the current approach handles better?