Provide support libraries for tools

[yarikoptic]

Eg to fetch, update and cache on user system newer versions. That might help to avoid needing new software release to just support more recent bids schema version.

[yarikoptic]

Perspective API (in Python lingua)

• get_versions(releases_only=True) - list of versions
• get(version='latest') - load and return schema structure
• update_cached(ttl=3600)

[tsalo]

Given how much the structure of the schema will probably fluctuate and the difficulties in changing BIDS releases after the fact, I think we should start backing up the release-associated schemas in this repository and we should try to keep the different versions of the schema up-to-date w.r.t. whatever the current version is. Not in terms of content, but in terms of the structure at least.

If we go that way, get functions in the code here will be very straightforward, since the actual files being loaded will already be in the repository.

[yarikoptic]

I think I had more of an idea for support tools for the layout here, not necessarily support tools to read bids schema itself.