Find genome location by nucleotide sequence

[alimanfoo]

Feature request from Tony Nolan. Add feature to enable search for genome positions using a query nucleotide sequence, instead of by gene or by genomic position. This makes life easier for e.g. design of CRISPR assays, where you want to find all locations with a specific motif. Without this feature the user has to do their own blast against the reference genome, record all coordinates, then do find by genomic region for each coordinate.