Updated sequences resource to return a better structure.  Also, changed options to include a data_type and an annotation field where the annotation field replaces all three fields organism, function, and ontology.  Instead the data_type that is defined determines what type of input is in the annotation field.
Fixed a couple bugs that were causing the MetagenomeOverview page to come up blank if the taxonomy stats were missing.  Also, changed the return structure of the sequences resource by editing md5_abundance_for_annotations, sequences_for_md5s, and sequences_for_annotation.  And, edited _get_annotation_map so it will return the md5 int to md5 string mapping.