fixed crash when adding an effect although none is selected and improved overall usability

git-svn-id: https://lmms.svn.sf.net/svnroot/lmms/trunk/lmms@954 0778d3d1-df1d-0410-868b-ea421aaaa00d

include/effect_select_dialog.h

@@ -76,19 +76,14 @@ public:
 
 signals:
 	void highlighted( const effectKey & _key );
-	void addPlugin( const effectKey & _key );
 	void doubleClicked( const effectKey & _key );
 	
 
-protected:
-	virtual void resizeEvent( QResizeEvent * );
-
-
 protected slots:
 	void rowChanged( const QModelIndex &, const QModelIndex & );
-	void onAddButtonReleased( void );
 	void onDoubleClicked( const QModelIndex & );
-	
+	void updateSelection( void );
+
 
 private:
 	QVector<plugin::descriptor> m_pluginDescriptors;

include/plugin.h

@@ -108,18 +108,28 @@ public:
 						user = l[1];
 					}
 				}
+
 				inline QString dumpBase64( void ) const
 				{
 					return( base64::encode(
 						QList<QVariant>()
 							<< name << user ) );
 				}
+
+				inline bool isValid( void ) const
+				{
+					return( desc != NULL &&
+							name != QString::null );
+				}
+
 				plugin::descriptor * desc;
 				QString name;
 				QVariant user;
 			};
+
 			typedef QList<key> keyList;
 
+
 			subPluginFeatures( plugin::PluginTypes _type ) :
 				m_type( _type )
 			{