Issue with readme example

[logankilpatrick]

I am trying to run the example from the readme and it errors out:

julia> using Codecs
[ Info: Precompiling Codecs [19ecbf4d-ef7c-5e4b-b54a-0a0ff23c5aed]

julia> data = "49276d206b696c6c696e6720796f757220627261696e206c696b65206120706f69736f6e6f7573206d757368726f6f6d"
"49276d206b696c6c696e6720796f757220627261696e206c696b65206120706f69736f6e6f7573206d757368726f6f6d"

julia> encoded = encode(Base64, encode(Zlib, data))
92-element Array{UInt8,1}:
 0x65
 0x4e
 0x6f
 0x64
 0x53
 0x77
 0x6b
 0x4f
 0x77
 0x43
    ⋮
 0x54
 0x51
 0x6c
 0x35
 0x51
 0x68
 0x68
 0x63
 0x43

julia> println(bytestring(encoded))
ERROR: UndefVarError: bytestring not defined
Stacktrace:
 [1] top-level scope at REPL[5]:1