Update README.md
QINIU_UNDEFINED_KEY
upload new api (up.qiniu.com)
update gist files
Merge pull request #77 from xushiwei/feature/new-put-api

upload new api (up.qiniu.com)
putpolicy
CHANGELOG
Merge pull request #80 from xushiwei/feature/new-put-api

putpolicy
Merge pull request #79 from qiniu/develop

Release v6.0.1