Simplify generating queries in lyrics providers

src/lyrics/lyricsprovider.h

@@ -33,18 +33,21 @@ struct LyricsSearchResult;
 class LyricsProvider : public QObject {
   Q_OBJECT
 
-public:
+ public:
   explicit LyricsProvider(const QString &name, QObject *parent);
 
+  typedef QPair<QString, QString> Param;
+  typedef QList<Param> ParamList;
+
   QString name() const { return name_; }
 
   virtual bool StartSearch(const QString &artist, const QString &album, const QString &title, quint64 id) = 0;
   virtual void CancelSearch(quint64 id) {}
 
-signals:
+ signals:
   void SearchFinished(quint64 id, const QList<LyricsSearchResult>& results);
 
-private:
+ private:
   QString name_;
 
 };