Filenames with double quotes broken #46

// ls works fine on the file
$ ls myfile\"hello\".flac 
myfile"hello".flac

// but echoprint-codegen fails
$ echoprint-codegen myfile\"hello\".flac 
[
{"error":"could not decode", "tag":0, "metadata":{"filename":"myfile\"hello\".flac"}}
]

// single quoting the filename fails as well
$ echoprint-codegen 'myfile"hello".flac' 
[
{"error":"could not decode", "tag":0, "metadata":{"filename":"myfile\"hello\".flac"}}
]

// just to show that echoprint-codegen works fine if the file has no double quotes
$ echoprint-codegen myfile.flac 
[
{"metadata":{"artist":"El Tri", "release":"No podemos volar", "title":"En el ultimo trago (dueto con Alberto Angel \"El Cuervo\")", "genre":"Latin", "bitrate":977,"sample_rate":44100, "duration":280, "filename":"myfile.flac", "samples_decoded":3090665, "given_duration":0, "start_offset":0, "version":4.12, "codegen_time":0.870392, "decode_time":1.150806}, "code_count":6930, "code":"eJzVvVuS.........