qmake: added mainwindow ui to qmake config to auto generate ui_mainwindow.h
icons: added more icons regarding net list management
PluginManager: added proper net management interface
RegulatedAVRProcessor: processEvents must be called periodically to allow signals to reach AVR logic
LEDLogic: assume low frequency signal to catch initial signals
netmanager: new net list manager table
misc: ui_mainwindow.h is no longer needed as it is generated automatically
misc: help window now launches web browser pointing to github repo
mainwindow: integrated netmanager beside console, new actions reflect the visibility of both windows

NOTE: instantiation of the net manager is done inside the ui_mainwindow.h