Bids-validator

- Quick fix (https://github.com/INCF/bids-validator/pull/548)
- Check if magnitude1 and magnitude2 images are 3D (not 4D - https://github.com/INCF/bids-validator/pull/543)

- Quickfix (https://github.com/INCF/bids-validator/pull/545)

* Display acqTime in acqTime format issues (535)
* Allow n/a values in acqTime field (539)
* Raise errors when JSON sidecars are found with no corresponding data file (358)
* Fieldmap regular expression fix (531)
* Throw a warning when _fieldmap.nii.gz is not accompanied by a _magnitude.nii.gz file (226)
* EEG coordsystem.json validation (533)
* Ensure phasediff is accompanied by _magnitude1 file (405)

* Use Issue.character for character offsets only
* Check schemas against merged dictionaries (438)

- Don't allow `fif.gz`.

* correctly show MEG in the summary (https://github.com/INCF/bids-validator/pull/490)
* updated automatic tests to CircleCI 2.0 (https://github.com/INCF/bids-validator/pull/495)
* added a link to GitHub repo on the web version of the validator (https://github.com/INCF/bids-validator/pull/494)
* updated requirements to Node 8 (https://github.com/INCF/bids-validator/pull/497)
* updated dependencies (https://github.com/INCF/bids-validator/pull/500)
* fix validation for KIT MEG systems (https://github.com/INCF/bids-validator/pull/499)
* new check: stimuli files present in /stimuli but not listed in any _events file (https://github.com/INCF/bids-validator/pull/501)
* show error code and label in the web validator (https://github.com/INCF/bids-validator/pull/505)
* prototype validation of EEG datasets - work in progress (https://github.com/INCF/bids-validator/pull/464)
* new check: proper value range for Echo Time (https://github.com/INCF/bids-validator/pull/506)
* new check: events with unusual onset times (https://github.com/INCF/bids-validator/pull/508)
* prototype validation of iEEG datasets - work in progress (https://github.com/INCF/bids-validator/pull/451)
* new check: slice timing array length (https://github.com/INCF/bids-validator/pull/509)
* new check: acq_time format (https://github.com/INCF/bids-validator/pull/507)
* new check: tsv files without data dictionaries (https://github.com/INCF/bids-validator/pull/503)
* added InstitutionDepartmentName to MEG JSON schema (https://github.com/INCF/bids-validator/pull/511)
* fixed effective echo spacing check (https://github.com/INCF/bids-validator/pull/516)