add toBytes (#14)

stew/byteutils.nim

@@ -123,3 +123,9 @@ func toHex*[N: static[int]](ba: array[N, byte]): string {.inline.} =
   ## Output is in lowercase
   ## No "endianness" reordering is done.
   toHexAux(ba)
+
+func toBytes*(s: string): seq[byte] =
+  ## Convert a string to the corresponding byte sequence - since strings in
+  ## nim essentially are byte sequences without any particular encoding, this
+  ## is almost a noop
+  cast[seq[byte]](s)