Add hotkey (F12) for switching perspective.

Switching perspective feature hides/restores all panels except of the main editor window for current FB.
So all available screen space is used for editor.

<?xml version='1.0' encoding='utf-8'?>
<BaseParams xmlns:xsd="http://www.w3.org/2001/XMLSchema" IEC_Channel="0" Name="py_ext_0"/>