* store method will store display_xref if it is set

* fetch methods correctly populate created display_xrefs now
* store method will store display_xref if it is set

Slice::project no longer forces projection to assembly_exception regions.  Not sure why it did this.

Added methods: hseq_region_name, hseq_region_strand, hseq_region_start and hseq_region_end, that return something if hslice is defined

addition of a $sth->finish

chained mapper was already being used even though faster regular mapper could usually have been used (accidentally commited with cache fix commit)

Modified store method slightly.  display_xref is now stored if set so update() does not need to be called as seperate step

Made global seq_region cache non-global.  Global cache for all dbs + mod_perl = very mysterious web bug.

In deprecated chr_name call, I've changed the code so it projects to the toplevel, not to the chromosome.  All species used to have chromosomes, so this always worked - the meaning of this call is now the same as it was, with the addded bonus that it works for species without chromosomes

Moved meta_coord table information retrieval/storage out of CoordSystemAdaptor and into new MetaCoordContainer class.  This was causing problems because the meta coord information should be stored/retrieved in the feature database and the coord system information should be stored/retrieved in the dna database