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/texteditor/basetexteditor.h

@@ -291,7 +291,7 @@ public:
     ~BaseTextEditor();
 
     static ITextEditor *openEditorAt(const QString &fileName, int line, int column = 0,
-                                     const QString &editorKind = QString());
+                                     const QString &editorId = QString());
 
     const Utils::ChangeSet &changeSet() const;
     void setChangeSet(const Utils::ChangeSet &changeSet);