Add BuildConfiguration classes

Each project has it's own BuildConfiguarion * classes, they'll get a
decent type safe interface and the setValue/value stuff will be removed.

src/plugins/cmakeprojectmanager/cmakeproject.h

@@ -74,6 +74,7 @@ public:
     QString displayNameForType(const QString &type) const;
 
     bool create(const QString &type) const;
+    bool clone(const QString &name, ProjectExplorer::BuildConfiguration *source) const;
 
 private:
     CMakeProject *m_project;