Implement legacy forge button!

Many refactors of the task system.
Progress dialog now accepts generic ProgressProvider objects

logic/BaseUpdate.cpp

@@ -7,7 +7,5 @@ BaseUpdate::BaseUpdate ( BaseInstance* inst, QObject* parent ) : Task ( parent )
 
 void BaseUpdate::updateDownloadProgress(qint64 current, qint64 total)
 {
-	// The progress on the current file is current / total
-	float currentDLProgress = (float) current / (float) total;
-	setProgress((int)(currentDLProgress * 100)); // convert to percentage
+	emit progress(current, total);
 }