FIX: switch dark mode bug

1.selected tool item in support,seam,mmu will be invalid after swich dark mode
2.add reset direction button in mmu
3.if don't switch dark mode in prepare page,toolbar doesn't change color

Change-Id: Ibaaaee5c0cc03f66682f5eb0daafcd143b9d9edc

src/slic3r/GUI/GLCanvas3D.hpp

@@ -701,6 +701,7 @@ public:
     bool init();
     void post_event(wxEvent &&event);
 
+    void on_change_toolbar_color_mode();
     void set_as_dirty();
     void requires_check_outside_state() { m_requires_check_outside_state = true; }