* Using single object to uploaded when files less than or equal to 67108864 bytes
* Using multi-part object to uploaded when files large than 67108864 bytes, and
calculate MD5SUMS in the upload process
* For Mkdir and Rmdir, Add block to wait qingstor service sync status to
handling extreme cases that try to create a just deleted bucket or delete
a just created bucket etc
Add new package qingstor to support QingStor API.
Add new unit test for its and tested through; But I commented
on some tests case because of some of the features of QingStor.
Add new docs for it.