0.2.0

Change List:

1. Support S3 multipart.
2. Embed web admin console into binary.
3. Add 30 minute timeout to admin console.
4. Support relative path as the value of node.disks.path in config file.
5. Add more S3 Rest APIs:
   HeadBucket
   HeadObject
   CopyObject
   DeleteObjects
   RenameObject
   CreateMultipartUpload
   UploadPart
   CompleteMultipartUpload
   AbortMultipartUpload
   ListMultipartUploads
   ListParts