Merge branch 'master' into docking

# Conflicts:
#	backends/imgui_impl_dx12.cpp
#	backends/imgui_impl_glfw.cpp
#	backends/imgui_impl_sdl.cpp
#	imgui_internal.h
#	imgui_widgets.cpp

backends/imgui_impl_vulkan.cpp

@@ -132,7 +132,7 @@ struct ImGui_ImplVulkan_Data
 
     ImGui_ImplVulkan_Data()
     {
-        memset(this, 0, sizeof(*this));
+        memset((void*)this, 0, sizeof(*this));
         BufferMemoryAlignment = 256;
     }
 };