commented out locuslink and OMIM as these are not used now. Removed Wormbase and used wormpep_id instead as this will not confilct with the external_db defined values

allow isa check also. Xref system uses a dbadptor as base class so has a different name but still isa

Added RefSeq_peptide_predicted and RefSeq_dna_predicted (as type 'PRED') to distinguish predictions from KNOWN RefSeq entries.

Added "search" for UTR transcripts when generating xref links.

Created; create xrefs & direct_xrefs from stable IDs for WormBase-imported genomes (e.g. elegans). Subclass of DatabaseParser.pm

Implemented store method for Marker objects in MarkerAdaptor, and added recursive store functionality to MarkerFeatureAdaptor