Merge master into tabs - last merge before obsolete old 'tabs' branch

# Conflicts:
#	examples/example_glfw_opengl2/example_glfw_opengl2.vcxproj
#	examples/example_glfw_opengl2/main.cpp
#	examples/example_glfw_opengl3/example_glfw_opengl3.vcxproj
#	examples/example_glfw_opengl3/main.cpp
#	examples/example_win32_directx11/example_win32_directx11.vcxproj
#	examples/example_win32_directx11/main.cpp