Implement continuous tape labels and path-based label shapes.

- Added "roll" as a special paper id
- Added roll_width attribute to draw tape in previews
- Updated Brother QL-500/* label templates
- Preserve print dialog settings between print jobs.
- Added path based labels for arbitrary shaped labels.
- Fleshed out implementation of continuous labels.

model/Distance.h

@@ -69,6 +69,7 @@ namespace glabels
 
 			Distance& operator+=( const Distance& d );
 			Distance& operator-=( const Distance& d );
+			Distance& operator*=( double f );
 			Distance operator-();
 
 			friend inline Distance operator+( const Distance& d1, const Distance& d2 );
@@ -100,6 +101,10 @@ namespace glabels
 }
 
 
+// Debugging support
+QDebug operator<<( QDebug dbg, const glabels::model::Distance& distance );
+
+
 //
 // Inline methods
 //
@@ -200,6 +205,13 @@ namespace glabels
 		}
 
 	
+		inline Distance& Distance::operator*=( double f )
+		{
+			mDPts *= f;
+			return *this;
+		}
+
+	
 		inline Distance Distance::operator-()
 		{
 			return Distance::pt( -mDPts );