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/coreplugin/iversioncontrol.h

@@ -46,7 +46,7 @@ public:
     IVersionControl(QObject *parent = 0) : QObject(parent) {}
     virtual ~IVersionControl() {}
 
-    virtual QString name() const = 0;
+    virtual QString displayName() const = 0;
 
     /*!
      * Returns whether files in this directory should be managed with this