added some more comprehensive RepeatMaskedSlice tests that were not in slice.t
added some more comprehensive RepeatMaskedSlice tests that were not in slice.t

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