Initial batch_dat_import

batch_dat_import function that batch imports .dat/.png files from a
design file (.xlsx). Output is a Map { dat file name => Epoch } that
can be passed to batch_analysis_import.

import_fenton_dat is updated to gracefully handle missing .dat and/or
.png files.
Show trial number in console output
Draft batch_analysis_import

Added PSFiles fixture(s), while reducing the size of the total fixture
to 10 epochs (20 files).

Still having an getting the right row in CSV results.
Corrected AnalysisRecord results writing