Addition of get_metabolites_from_pathway.py

New function get_metabolites_from_pathway.py takes a pathway and an output file and gets the compounds involved with that pathway.  Changed get_compound_names() from parse_KEGG.py to get_co_info() which returns a named tuple with compound ids, names, formulas, and mass.  This probably breaks things (make_metab_network.py).
A ton of changes

So metab_network was updated to use the new KEGG_Parser object from parse_KEGG.py.  That object was added to parse_KEGG.  parse_picrust_KO_table.py has bugfixes.  anal_comp_metab.py was written to investigate pathways and metabolites that are utilized by given genomes.  get_genome.sh and make_gg_genomes.py are different ways to parse the picrust KO table to get out genome content information.