Added SQL functionality to handle duplicates for inserting into the object_xref table to return the duplicated object_xref_is rather than 0
Applied the patch supplied by Andy to avoid issues with SQLite.
Merge branch 'master' of https://github.com/markmcdowall/ensembl into markmcdowall-master
Merge branch 'markmcdowall-master'
Merge branch 'master' of https://github.com/Ensembl/ensembl