Reduce redundante call to bytes.ToLower and substitute the last call by an home made version doing the conversion in place

Former-commit-id: d9ea22f649d97be352f8dbb37acc1495df830118

pkg/obiformats/embl_read.go

@@ -141,10 +141,10 @@ func _ParseEmblFile(source string, input <-chan _FileChunk, out obiiter.IBioSequ
 				}
 			case line == "//":
 				sequence := obiseq.NewBioSequence(id,
-					bytes.ToLower(seqBytes.Bytes()),
+					seqBytes.Bytes(),
 					defBytes.String())
 				sequence.SetSource(source)
-				
+
 				sequence.SetFeatures(featBytes.Bytes())
 
 				annot := sequence.Annotations()