Implement handling of subjects with BIDS data but no session layers

[alyssadai]

• Added a create_session utility function + test

Closes #82

[coveralls]

Pull Request Test Coverage Report for Build 4257080996

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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Details

• 24 of 24 (100.0%) changed or added relevant lines in 2 files are covered.
• 3 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 98.143%

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Files with Coverage Reduction	New Missed Lines	%
bagelbids/cli.py	3	96.25%

Totals
Change from base Build 4247749074:	-0.2%
Covered Lines:	370
Relevant Lines:	377

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💛 - Coveralls

[surchs]

very nice @alyssadai , as discussed in the call, could you please change the create_session to something like create_acquisitions and make sure it returns a newly created list (that can be empty).

[surchs]

thanks for this @alyssadai, all looks very good! Left some 🍒 comments, take a look, but good to go