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.

glabels/File.cpp

@@ -56,12 +56,13 @@ namespace glabels
 		{
 			auto* model = new model::Model();
 			model->setTmplate( tmplate );
-			model->clearModified();
-
+			
 			// Intelligently decide to rotate label by default
 			const model::Frame* frame = tmplate->frames().first();
 			model->setRotate( frame->h() > frame->w() );
 
+			model->clearModified();
+
 			// Either apply to current window or open a new one
 			if ( window->isEmpty() )
 			{