Make basic CBF and BASIL mutually exclusive

[tsalo]

Summary

Sudipto Dolui recommends making the basic CBF the default, with the advanced options recommended in cases of low-quality data.

The goal is to provide one set of CBF outputs, in order to dissuade p-hacking (intentional or otherwise).

[tsalo]

SCORE/SCRUB run on the basic CBF results, so instead the options should be:

1. CBF
2. CBF+SCORE/SCRUB
3. BASIL CBF

[tsalo]

The good news is that BASIL CBF should be able to handle multi-PLD, Q2TIPS, and PASL without BolusCutOff.

[tsalo]

It doesn't look like BASIL can output CBF time series, although the primary output should be the mean CBF, so it's probably not a big deal.