Datalad-neuroimaging

Minor bugfix release to account for changes in pybids and datalad

- pybids:
- demand pybids >=0.9.2
- account for new field "extension" provided by BIDS now
- use get_dataset_description if available
- pandas:
- use .iloc instead of deprecated .ix
- datalad
- use -d^ instead of deprecated (in 0.12) -S in an example script

Minor quick bugfix release to demand pybids < 0.9 since we are not yet fully
ready for its full glory

Minor bugfix release
- revert back to old ways of installing package data so test data and procedures
get properly installed

- include a procedure 'cfg_bids' to configure BIDS datasets
- fix several issues with troublesome dependency declarations

- Make compatible with (and demand) pybids 0.7.{0,1}. 0.7.0 introduced
change of terms: modality -> suffix, and type -> datatype, which would now
require to either reaggregate all previous metadata or somehow fixup
in-place existing metadata files. And for 0.7.1 workaround was added to
not return `suffix` at least when participants.tsv was queried.
- Make compatible with pydicom 1.0 in treatment of MultiValue
- Refactorings:
- tests:
- use `export_archive` instead of plain `tarfile.open`
- make compatible with recent (0.11.x) DataLad which now extract annex
keys etc

- Assorted improvements of the BIDS metadata extractor performance on datasets
in the wild.