MRG : EEG Reference reloaded !

@wmvanvliet what we do is the following:
- we read the raw data wihtout adding any reference
- we filter the raw data between 0.5 and 30 Hz
- we form epochs (still without reference)
- we use a variance and kurtosis based iterative outlierdetection that takes finds bad channels, either constantly flat or constantly noisy, but also channels that have show massive changes in between epoch variance
- this results in between 25 and 5 out of 257 bad channels and 30-200 bad epochs out of 700
- we set a common average reference
- we compute ICA and reject artefact components
- we interpolate bad channels

Filtering at the epochs stage is a bad idea. But I'm not sure why you would need a common avaerage reference for filtering raw data. Importantly, referencing does not make sense before rejecting bad channels. With EEG you often have non stationary bads, also across 8 runs, there's different bads. That's why we process epoched data.