Merge pull request #35 from qiniu/master

v3.4.1 - add :async_options for uploadToken
mv appkey outside and encrypted
Merge pull request #36 from why404/feature/encrypt_appkey

mv appkey outside and encrypted
rm encrypted appkey
fix travis env syntax
used before_script instead of env vars in .travis.yml
add :return_body option for Qiniu::RS.generate_upload_token()
Merge pull request #39 from why404/feature/return_body

add :return_body option for Qiniu::RS.generate_upload_token()
Merge pull request #38 from why404/feature/fix_env_appkey

rm encrypted appkey
release v3.4.2 for uploadToken[:return_body] #40 .
update README.md
Merge pull request #41 from why404/release/v3.4.2

Release/v3.4.2 - uploadToken[:return_body]