make heudiconv TODOs break bids-validator

[satra]

Summary

i have seen some datasets converted that have TODOs but pass the validator, but fail when people are trying to run downstream scripts/workflows. i think heudiconv should intentionally force people to address the TODOs by making those files fail validation. the easy example to point to is events.tsv.

[yarikoptic]

Do you have an example of a script/workflow which trips? AFAIK all our todos as following the bids spec and thus validator is silent. Events file included. I suspect that may be the tools you had in mind are buggy? ;-) I will not charge their developers for the awesome test cases heudiconv provides them with to help them catch all the bugs ;-)

Having said all that I wouldn't mind validator having a dedicated warning to alert about todos

[satra]

fitlins breaks on bunch of things depending on what stats models is being evaluated, but the one that tripped it most recently was an empty events.tsv for one session but not another.