Get Codon frequency from bicodons.

Input format should match that provided by CoCoPUTs (https://dnahive.fda.gov/dna.cgi?cmd=codon_usage&id=537&mode=cocoputs; e.g. https://dnahive.fda.gov/dna.cgi?cmd=objFile&ids=537&filename=Refseq_Bicod.tsv&raw=1).

Input row of interest is selected by the combination of the provided taxid and organelle.

Translation table identifiers are based upon NCBI standards (https://www.ncbi.nlm.nih.gov/Taxonomy/Utils/wprintgc.cgi).

Example of CoCoPUTs style bicodon input, the majority of bicodons (codon pairs) have been removed in this example, for brevity:

Division	Assembly	Taxid	Species	Organelle	Translation Table	# CDS	# Codon Pairs	aaaaaa	aaaaac	aaaaag	aaaaat	...
custom	hg38	9606	Homo sapiens	genomic	1	4	859	0	0	0	1	...