chat: multi-lines input: - text input is now multi-lines and grows with the text (up to a max) - on touch devices (i.e. on Android), an icon is added to the right to send the message, allowing to use virtual enter key for multi-lines messages

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