Add liblastfm2 and make tomahawk build against it

thirdparty/liblastfm2/demos/demo1.cpp

@@ -0,0 +1,95 @@
+/*
+   This software is in the public domain, furnished "as is", without technical 
+   support, and with no warranty, express or implied, as to its usefulness for 
+   any purpose.
+*/
+#include <lastfm.h> // this includes everything in liblastfm, you may prefer 
+#include <QtCore>   // to just include what you need with your project. Still
+#include <QtGui>    // we've given you the option.
+#include <QPointer>
+#include <QNetworkReply>
+
+class ArtistList : public QListWidget
+{
+    Q_OBJECT
+    
+    QPointer<QNetworkReply> reply;
+    QString artist;
+    
+public:
+    ArtistList()
+    {
+        connect( this,
+                 SIGNAL(itemActivated( QListWidgetItem* )),
+                 SLOT(onItemActivated( QListWidgetItem* )) );
+    }
+    
+    void getSimilar( const QString& artist )
+    {
+        this->artist = artist;
+        setWindowTitle( "Loading " + artist + "..." );
+        
+        // deleting a reply cancels the request and disconnects all signals
+        delete reply;
+        reply = lastfm::Artist( artist ).getSimilar();
+        connect( reply, SIGNAL(finished()), SLOT(onGotSimilar()) );
+    }
+    
+private slots:
+    void onGotSimilar()
+    {
+        QNetworkReply* r = static_cast<QNetworkReply*>(sender());
+        // always enclose retrieval functions in a try block, as they will
+        // throw if they can't parse the data
+        try
+        {
+            // you decode the response using the equivalent static function
+            QMap<int, QString> artists = lastfm::Artist::getSimilar( r );
+
+            clear();
+
+            // we iterate backwards because best match is last because the map
+            // sorts itself by key
+            QStringListIterator i( artists.values() );
+            i.toBack();
+            while (i.hasPrevious())
+                addItem( i.previous() );
+                
+            setWindowTitle( artist );
+        }
+        catch (std::runtime_error& e)
+        {
+            // if getSimilar() failed to parse the QNetworkReply, then e will 
+            // be of type lastfm::ws::ParseError, which derives 
+            // std::runtime_error
+            qWarning() << e.what();
+        }
+    }
+    
+    void onItemActivated( QListWidgetItem* item )
+    {
+        getSimilar( item->text() );
+    }
+};
+
+
+int main( int argc, char** argv )
+{
+    QApplication app( argc, argv );
+    app.setApplicationName( "liblastfm" ); // used to generate UserAgent
+    
+    // all you need for non-authenticated webservices is your API key
+    // this one is a public one, it can only do artist.getSimilar calls, so
+    // I suggest you don't use it :P
+    lastfm::ws::ApiKey = "b25b959554ed76058ac220b7b2e0a026";
+
+    ArtistList artists;
+    artists.getSimilar( "nirvana" );
+    artists.resize( 300, 400 ); // Qt picks truly asanine default sizes for its widgets
+    artists.show();
+
+    return app.exec();
+}
+
+
+#include "demo1.moc"