oss-sign-utils v1.0.2

阿里云签名工具

替换了crypto和buffer, 解决阿里云jssdk太大的问题

Authorization字段计算的方法

Authorization = "OSS " + AccessKeyId + ":" + Signature
Signature = base64(hmac-sha1(AccessKeySecret,
            VERB + "\n"
            + Content-MD5 + "\n"
            + Content-Type + "\n"
            + Date + "\n"
            + CanonicalizedOSSHeaders
            + CanonicalizedResource))