formatOutputBytes = function (param, name) {
    var matches = name.match(/^bytes([0-9]*)/);
    var size = parseInt(matches[1]);
    return '0x' + param.staticPart().slice(0, 2 * size);
}
Should be used to format output bytes

@method formatOutputBytes
@param {SolidityParam} left-aligned hex representation of string
@param {String} name type name
@returns {String} hex string