Merge branch 'master' into docking

# Conflicts:
#	backends/imgui_impl_opengl3.cpp
#	backends/imgui_impl_win32.cpp

examples/example_glfw_opengl3/main.cpp

@@ -7,6 +7,7 @@
 #include "imgui_impl_glfw.h"
 #include "imgui_impl_opengl3.h"
 #include <stdio.h>
+#define GL_SILENCE_DEPRECATION
 #if defined(IMGUI_IMPL_OPENGL_ES2)
 #include <GLES2/gl2.h>
 #endif