Changes to _slice_fetch: simpify SQL if slice is an SNP - only 1bp long. Functionality suggested by Ensembl Genomes, used when building a variation DB.
Changes to _slice_fetch: simpify SQL if slice is an SNP - only 1bp long.
Functionality suggested by Ensembl Genomes, used when building a variation DB.

Ensembl/ensembl,Ensembl/ensembl,at7/ensembl,muffato/ensembl,Ensembl/ensembl,mjg17/ensembl,mjg17/ensembl,james-monkeyshines/ensembl,muffato/ensembl,willmclaren/ensembl,mjg17/ensembl,at7/ensembl,at7/ensembl,Ensembl/ensembl,mjg17/ensembl,danstaines/ensembl,muffato/ensembl,danstaines/ensembl,at7/ensembl,muffato/ensembl,james-monkeyshines/ensembl,james-monkeyshines/ensembl,danstaines/ensembl,james-monkeyshines/ensembl,willmclaren/ensembl