Improve support for eland searching a single fasta containing multiple records.

Improve support for eland searching a single fasta containing multiple records.
the problem was that I was assuming / was a path seperator between genome
directory name and chromosome, but eland was also reporting it as
fasta file name / fasta record.

By happy accident in genome map, the fasta file with multiple records would
be stored in the GenomeMap dictionary as having the same name, value pair
while things that had the genome encoded would be fasta filename mapping to
genome/fasta filename.

as a result it appears that splitting a mapped item on the path seperator /
and then looking the "base path" up in the genome map will allow me to
determine if an element is a genome directory "path" or a multi record
fasta file by its absence (for genome dirs) or presence (for multi
fasta records)