Merge branch 'master' into docking

# Conflicts:
#	backends/imgui_impl_dx10.cpp
#	backends/imgui_impl_dx11.cpp
#	backends/imgui_impl_dx12.cpp
#	backends/imgui_impl_dx9.cpp
#	backends/imgui_impl_glfw.cpp
#	backends/imgui_impl_opengl3.cpp
#	backends/imgui_impl_sdl.cpp
#	backends/imgui_impl_vulkan.cpp
#	backends/imgui_impl_win32.cpp
#	imgui.cpp
#	imgui_internal.h

examples/example_sdl_opengl2/main.cpp

@@ -106,7 +106,7 @@ int main(int, char**)
 
         // Start the Dear ImGui frame
         ImGui_ImplOpenGL2_NewFrame();
-        ImGui_ImplSDL2_NewFrame(window);
+        ImGui_ImplSDL2_NewFrame();
         ImGui::NewFrame();
 
         // 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!).