Make method naming more consistent.

* Use id() for methods returning a string used to represent
    some type of object.
  * Use displayName() for strings that are meant to be user
    visible.
  * Quieten some warnings while touching the files anyway.
  * Move Factories to their products in the plugins where that
    was not done before.

Reviewed-by: dt

src/plugins/git/clonewizard.h

@@ -44,7 +44,7 @@ public:
     // IWizard
     virtual QIcon icon() const;
     virtual QString description() const;
-    virtual QString name() const;
+    virtual QString displayName() const;
 
 protected:
     // BaseCheckoutWizard