Button, ToggleButton and slider updated. Error to warning when building

Button fixed so it doesn't release until it gets feedback from plc

Toggle button changed so it makes changes instantly. There was too big delay if we waited for feedback.

Slider added new features need some changes for final version.

Beremiz's user manual
=====================

Contents:

.. toctree::
   :maxdepth: 2

   install
   start
   edit
   build
   connectors
   debug