[gtk] (21 commits) Non-fast-forward update to branch wip.win32.fixes

[Chun-wei Fan <fanchunwei src gnome org>]

The branch 'wip.win32.fixes' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  b21ff92... media/gstreamer: Support using GL for video for Windows
  1cc6883... gtkgstsink.c: Support EGL on Windows as well
  1f83a23... gtkgstsink.c: Fix up thinko
  280a4c2... gtkgstsink.c: Avoid g_setenv()
  52d0828... gtkgstsink.c: Win32: Limit GL API to gles2 when using EGL
  2113a41... gstglsink.c: Some cleanups
  6c7ba80... demos/gtk-demo|widget-factory: Temporarily disable gui_app 
  9725fbb... gtkgstsink.c: Check GST_GL_HAVE_PLATFORM_EGL correctly
  15b1f9c... gtkgstsink.c: Call gst_gl_display_filter_gl_api() always on

Commits added to the branch:

  fb6c6c8... checkbutton: Don't allow to uncheck radios by activating th (*)
  bff7ac4... popover: Update docs (*)
  430be6f... Merge branch 'popover-docs' into 'master' (*)
  0017b4b... icons: Fix switch-off icon (*)
  94b0907... Merge branch 'wip/exalm/switch-icons-2' into 'master' (*)
  ab6a5be... Fix documentation syntax (*)
  8ba16eb... Documentation fixes (*)
  7fe0610... introspection: Stop using allow-none (*)
  4a0d3d7... docs: Reduce redundancy (*)
  345edb8... Merge branch 'doc-tweaks' into 'master' (*)
  f5bd9f7... Merge branch 'wip/exalm/check-activate' into 'master' (*)
  d00e546... media/gstreamer: Support using GL for video for Windows
  fc2df44... gtkgstsink.c: Support EGL on Windows as well
  5464cd9... gtkgstsink.c: Fix up thinko
  9c17635... gtkgstsink.c: Avoid g_setenv()
  ef0a703... gtkgstsink.c: Win32: Limit GL API to gles2 when using EGL
  58cd828... gstglsink.c: Some cleanups
  e21c201... demos/gtk-demo|widget-factory: Temporarily disable gui_app 
  334bdf8... gtkgstsink.c: Check GST_GL_HAVE_PLATFORM_EGL correctly
  45645a9... gtkgstsink.c: Call gst_gl_display_filter_gl_api() always on
  79098e5... gtkgstsink.c: Acquire GstGL API manually if needed

(*) This commit already existed in another branch; no separate mail sent