fix for errors in getting a database connection when in disconnect_when_inactive set and is being called to0 fast for the system to keep up with

no need for 12 drosophila_\* .pm files all with the same rouens in apart form one line so created a master drosphila.pm file and all the other inherit from this one

changed the setting of the accession for unigene to call a subroutine so that this can be overwritten in an alternative version to be used here but ensembl genomes to use the original still

For unigene use the same acc and label to make sure only one copy per gene, previously the acc was the uniprot accession

for the benefit of Region Report tool

as records for old release are still set to current
Added query for species with new variation positions, using new field added to changelog
'variation_pos_changed'

Added option to override db name.

Also minor POD corrections.

Update schema version.

Functionality suggested by Ensembl Genomes, used when building a variation DB.