java sdk doc fix
update java sdk doc
Merge pull request #43 from why404/feature/doc_fix

Feature/doc fix
HttpClient use connpool
Merge pull request #45 from xushiwei/feature/conn

HttpClient use connpool
CHANGELOG
Merge pull request #47 from xushiwei/feature/conn

CHANGELOG v2.5.0
Merge pull request #46 from qiniu/develop

Release v2.5.0