Notebook unittests for TellseqA and TellseqD notebooks (#357)

* modify tellseq notebook D and associated unit tests to use same approach as others, add support for checking autoconstructed output paths

* modify tellseq notebook A to support added unit tests, update test files to reflect change in add_controls output, add ability to "zero out" paths in output files so test files match

Author: AmandaBirmingham