Pointer cleanup (#242)

- Made greater use of smart pointers, eliminating many instances of manual memory management
- Do not use pointers at all for many non-polymorphic classes
- Assorted other code cleanup

model/FrameContinuous.h

@@ -35,15 +35,15 @@ namespace glabels
 			Q_DECLARE_TR_FUNCTIONS(FrameContinuous)
 
 		public:
-			FrameContinuous( const Distance& w,
-			                 const Distance& hMin,
-			                 const Distance& hMax,
-			                 const Distance& hDefault,
-			                 const QString&  id = "0" );
+			FrameContinuous( Distance       w,
+			                 Distance       hMin,
+			                 Distance       hMax,
+			                 Distance       hDefault,
+			                 const QString& id = "0" );
 
 			FrameContinuous( const FrameContinuous& other ) = default;
 
-			Frame* dup() const override;
+			std::unique_ptr<Frame> clone() const override;
 
 			Distance w() const override;
 			Distance h() const override;
@@ -52,16 +52,18 @@ namespace glabels
 			Distance hMax() const;
 			Distance hDefault() const;
 
-			void setH( const Distance& h ) override;
+			bool setH( Distance h ) override;
 
-			QString sizeDescription( const Units& units ) const override;
+			QString sizeDescription( Units units ) const override;
 
-			bool isSimilarTo( Frame* other ) const override;
+			bool isSimilarTo( const Frame& other ) const override;
 
 			const QPainterPath& path() const override;
 			const QPainterPath& clipPath() const override;
-			QPainterPath marginPath( const Distance& xSize,
-			                         const Distance& ySize ) const override;
+			QPainterPath marginPath( Distance xSize, Distance ySize ) const override;
+
+                        // Debugging support
+			void print( QDebug& dbg ) const override;
 
 
 		private:
@@ -78,8 +80,4 @@ namespace glabels
 }
 
 
-// Debugging support
-QDebug operator<<( QDebug dbg, const glabels::model::FrameContinuous& frame );
-
-
 #endif // model_FrameContinuous_h