#1 Number of ADCs for PlotWidget should be determined by opened file, if not plotting life data

If you load an .out file in the GUI and open a plot widget, it will show controls for the number of ADCs from the board_config, even though the loaded .out file might have been recorded with a different number of channels. Easy workaround could be to "grey out" the checkboxes for channels which do not exist in the loaded dataset.