IDocument: Make mimeType a value member

Change-Id: I2e90ccf0a45ae8d00bcd00ec77fe0d9776f2f119
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/cmakeprojectmanager/cmakeproject.h

@@ -194,7 +194,6 @@ public:
 
     QString defaultPath() const;
     QString suggestedFileName() const;
-    QString mimeType() const;
 
     bool isModified() const;
     bool isSaveAsAllowed() const;