plugin chat: e2e encryption improvments: OTR buttons has been replaced with a more generic one, which use new encryption mechanisms to retrieve all current encryption algorithms (+ a button for plain text). "refresh" and "authentify" buttons for OTR are temporarily removed. Encryption state is checked on chat widget startup, and current encryption method is selected (it will appear with a different background in encryption menu).

-e git+https://github.com/kivy/kivy.git#egg=kivy
-e hg+https://repos.goffi.org/sat#egg=sat
-e .