Make reader beep after card successfully read

[robinsmidsrod]

Implement the codes mentioned in this gist to indicate that card UID has been read successfully:

https://gist.github.com/nixme/2717287

[robinsmidsrod]

The relevant parts are these:

# Disable the standard buzzer when a tag is detected (Section 6.7). It sounds
# immediately after placing a tag resulting in people lifting the tag off before
# we've had a chance to read the ID.
card.transmit "\xFF\x00\x52\x00\x00"

# Ask card for UID in APDU format (Section 5.1)
response = card.transmit("\xFF\xCA\x00\x00\x04").unpack('C*')

# Beep and change LED to orange to signal user we've read the tag.
# (Section 6.2)
card.transmit "\xFF\x00\x40\xCF\x04\x03\x00\x01\x01" rescue nil