SVGHMI: better handling of page switch fade-out.

- In cases or relative jump to current page, page was keeping black after switch.
- Now keep track of undergoing page switch without comparing subscribed page to visible page.

.. Beremiz documentation master file

Beremiz's documentation
=======================

Contents:

.. toctree::
   :maxdepth: 2

   overview
   manual/index
   standards