Adds method to copy string to clipboard

	This commit adds a method to the Clipboard class to copy a generic string to the clipboard, using the given MimeType from our enum. That is used in the PianoRoll to copy notes, saving a few lines on PianoRoll.cpp by moving some of the clipboard logic to the Clipboard class.

include/Clipboard.h

@@ -45,6 +45,8 @@ class Clipboard
 	static void copy( JournallingObject * _object );
 	static const QDomElement * getContent( const QString & _node_name );
 
+	static void copyString( const QString & str, MimeType mT );
+
 	// Helper methods for String Pair data
 	static void copyStringPair( const QString & key, const QString & value );
 	static QString decodeKey( const QMimeData * mimeData );

src/core/Clipboard.cpp

@@ -60,6 +60,17 @@ const QDomElement * Clipboard::getContent( const QString & _node_name )
 
 
 
+void Clipboard::copyString( const QString & str, MimeType mT )
+{
+	QMimeData *content = new QMimeData;
+
+	content->setData( mimeType( mT ), str.toUtf8() );
+	QApplication::clipboard()->setMimeData( content, QClipboard::Clipboard );
+}
+
+
+
+
 void Clipboard::copyStringPair( const QString & key, const QString & value )
 {
 	QString finalString = key + ":" + value;

src/gui/editors/PianoRoll.cpp

@@ -3890,10 +3890,7 @@ void PianoRoll::copyToClipboard( const NoteVector & notes ) const
 		clip_note.saveState( dataFile, note_list );
 	}
 
-	QMimeData * clip_content = new QMimeData;
-	clip_content->setData( Clipboard::mimeType( Clipboard::Default ), dataFile.toString().toUtf8() );
-	QApplication::clipboard()->setMimeData( clip_content,
-							QClipboard::Clipboard );
+	Clipboard::copyString( dataFile.toString(), Clipboard::Default );
 }