Added io.WantMoveMouse flags from Nav branch so Examples/Binding can already implement it. (#787)

imgui.h

@@ -855,6 +855,7 @@ struct ImGuiIO
     bool        WantCaptureMouse;           // Mouse is hovering a window or widget is active (= ImGui will use your mouse input). Use to hide mouse from the rest of your application
     bool        WantCaptureKeyboard;        // Widget is active (= ImGui will use your keyboard input). Use to hide keyboard from the rest of your application
     bool        WantTextInput;              // Some text input widget is active, which will read input characters from the InputCharacters array. Use to activate on screen keyboard if your system needs one
+    bool        WantMoveMouse;              // [BETA-NAV] MousePos has been altered. back-end should reposition mouse on next frame. used only if 'NavMovesMouse=true'.
     float       Framerate;                  // Application framerate estimation, in frame per second. Solely for convenience. Rolling average estimation based on IO.DeltaTime over 120 frames
     int         MetricsAllocs;              // Number of active memory allocations
     int         MetricsRenderVertices;      // Vertices output during last call to Render()