* 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
* use rclone's http.Client for bwlimit, logging, etc
* remove extraneous fmt.Sprintf from logging
* fix icon in docs
* add docs about --fast-list
* hoist md5 regexp compilation out of function
* create container if necessary on server side copy
* keep note of whether the container has been deleted
* build constraint not to compile for plan9
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.
