Remove all trailing spaces

No real changes, just clean up sources by removing trailing spaces from
all the non-generated files.

This should hopefully avoid future commits mixing significant changes
with insignificant whitespace ones.

interface/wx/mousestate.h

@@ -108,7 +108,7 @@ public:
     void SetX(wxCoord x);
     void SetY(wxCoord y);
     void SetPosition(const wxPoint& pos);
-    
+
     void SetLeftDown(bool down);
     void SetMiddleDown(bool down);
     void SetRightDown(bool down);
@@ -116,7 +116,7 @@ public:
     void SetAux2Down(bool down);
 
     void SetState(const wxMouseState& state);
-    
+
 };