Merge branch 'master' into docking

# Conflicts:
#	backends/imgui_impl_dx10.cpp
#	backends/imgui_impl_dx10.h
#	backends/imgui_impl_vulkan.h
#	backends/imgui_impl_win32.cpp
#	docs/CHANGELOG.txt
#	examples/README.txt
#	examples/example_glfw_opengl2/main.cpp
#	examples/example_glfw_opengl3/main.cpp
#	examples/example_glfw_vulkan/main.cpp
#	examples/example_sdl_directx11/main.cpp
#	examples/example_sdl_opengl2/main.cpp
#	examples/example_sdl_opengl3/main.cpp
#	examples/example_sdl_vulkan/main.cpp
#	examples/example_win32_directx10/main.cpp
#	examples/example_win32_directx11/main.cpp
#	examples/example_win32_directx12/main.cpp
#	examples/example_win32_directx9/main.cpp
#	imgui.cpp
#	imgui.h
#	imgui_demo.cpp
#	imgui_internal.h

examples/example_sdl_opengl2/main.cpp

@@ -1,6 +1,7 @@
-// dear imgui: standalone example application for SDL2 + OpenGL
-// If you are new to dear imgui, see examples/README.txt and documentation at the top of imgui.cpp.
+// Dear ImGui: standalone example application for SDL2 + OpenGL
 // (SDL is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan/Metal graphics context creation, etc.)
+// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
+// Read online: https://github.com/ocornut/imgui/tree/master/docs
 
 // **DO NOT USE THIS CODE IF YOUR CODE/ENGINE IS USING MODERN OPENGL (SHADERS, VBO, VAO, etc.)**
 // **Prefer using the code in the example_sdl_opengl3/ folder**
@@ -60,7 +61,7 @@ int main(int, char**)
         style.Colors[ImGuiCol_WindowBg].w = 1.0f;
     }
 
-    // Setup Platform/Renderer bindings
+    // Setup Platform/Renderer backends
     ImGui_ImplSDL2_InitForOpenGL(window, gl_context);
     ImGui_ImplOpenGL2_Init();