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/Vendor.cpp

@@ -26,7 +26,9 @@ namespace glabels
 	namespace model
 	{
 
-		Vendor::Vendor( const QString &name, const QString &url ) : mName(name), mUrl(url)
+		Vendor::Vendor( const QString &name, const QString &url )
+			: mName(name),
+			  mUrl(url)
 		{
 			// empty
 		}