Merge branch 'thedmd/extra-keys-v1' into docking

# Conflicts:
#	backends/imgui_impl_glfw.cpp
#	backends/imgui_impl_glfw.h
#	backends/imgui_impl_osx.h
#	backends/imgui_impl_osx.mm
#	backends/imgui_impl_sdl.cpp
#	backends/imgui_impl_sdl.h
#	backends/imgui_impl_win32.cpp
#	backends/imgui_impl_win32.h
#	imgui.cpp
#	imgui.h