Master layout: lose or inherit fullscreen on deliberate window switching (#1213)

* Master layout: Lose fullscreen status when deliberately switching away from a fullscreen window

* Master layout: implemented inherit_fullscreen config parameter

When set, if you are on a fullscreen window and you cycle to the next,
swap master, etc, it will be automatically fullscreened.

src/layout/MasterLayout.hpp

@@ -75,6 +75,8 @@ private:
     void                calculateWorkspace(const int&);
     CWindow*            getNextWindow(CWindow*, bool);
     int                 getMastersOnWorkspace(const int&);
+    bool                prepareLoseFocus(CWindow*);
+    void                prepareNewFocus(CWindow*, bool inherit_fullscreen);
 
     friend struct SMasterNodeData;
     friend struct SMasterWorkspaceData;