Breaking changes in Kivy

This is a draft of API breaks which were merged in Kivy.

1.10.0

#3891 ButtonBehavior.always_release defaults to False
#4132 ButtonBehavior.MIN_STATE_TIME was removed
#4168 kivy.metrics.metrics was removed
#4211 TextInput.background_disabled_active was removed
#4254 kivy.utils.platform is now a string and not a callable
#4603 Made App.on_pause default to True
#4819 Remove extension support
#4224 Remove pygst (audio, video, camera), gi (audio, video) and videocapture (camera) providers

1.10.1