Support comments in hex and bin strings

[mpilquist]

Example usage (from tests):

val packet = hex"""
  ; Start of first packet from https://wiki.wireshark.org/uploads/__moin_import__/attachments/SampleCaptures/mpeg2_mp2t_with_cc_drop01.pcap
  01 00 5e 7b ad 47 00 0c db 78 7d 00 08 00                      ; Ethernet header
  45 00 05 40 b6 9f 40 00 0c 11 de 95 51 a3 96 3c e9 70 03 28    ; IPv4 header
  c3 50 15 7c 05 2c 00 00                                        ; UDP header
  47 02 00 1e                                                    ; MP2T header
"""