allowing to add 'Levels' for the task-x_events.json

[CPernet]

Running bids_export as command line and passing a structure for 'eInfoDesc'.
For instance

eventsinfo.value.LongName       = 'Event marker';
eventsinfo.value.Description    = 'Marker value associated with the event';

Those markers can have levels as per the BIDS specification, we should, therefore, be able to pass cells of cells that are written by jsonwrite.m as concatenated arrays (as per spec)

 eventsinfo.value.Levels = {{'Marker1', '60dB sound'}, {'Marker1', '70dB sound'}, {'Marker1', '80dB sound'}}

[dungscout96]

This syntax should work. Can you check?

eventsinfo.value.Levels.Marker1 = '60dB sound';
eventsinfo.value.Levels.Marker2 = '70dB sound';
eventsinfo.value.Levels.Marker3 = '80dB sound';