Convert first nucleotide of sequence to lower case in fasta reader

Former-commit-id: 856bb3a39a4f1143a34b1f8b4d8d12b0151c0c3e

pkg/obiformats/fastaseq_read.go

@@ -219,6 +219,9 @@ func ParseFastaChunk(source string, ch FastxChunk) *obiiter.BioSequenceBatch {
 			if !is_end_of_line {
 				// Beginning of sequence
 				start = i
+				if C >= 'A' && C <= 'Z' {
+					ch.Bytes[current] = C + 'a' - 'A'
+				}
 				current = i + 1
 				state = 6
 			}