Add force_dispatch option to properties
Merge pull request #2747 from bionoid/force_dispatch

Add force_dispatch option to properties
doc: tweaks to uix/pagelayout.py
doc: fixed formatting in graphics/vertex_instructions.pyx
Add args param to get_preoprty_observers.
Add new unbind_uid method to allow unbinding by matching a uid.
Add the unbind_uid code to EventDispatcher and Property.
Fix Observable to accept kwargs, and add unbind_uid support to make it compatible with current lang.
Add docs to unbind_uid.
Update lang to use unbind_uid instead of fast_unbind.
Fix unbind_uid callback.
Merge branch 'master' of https://github.com/kivy/kivy into bind-restore-list