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]
fix links
Update README.md

correct the title
Update README.md
Merge pull request #49 from longshanksmo/fix/lost_link

Fix/lost link
use new account & correct test code
Merge pull request #51 from longshanksmo/fix/test_account

use new account & correct test code
disable ruby-head on travis
Merge remote-tracking branch 'origin/master' into develop

Conflicts:
	docs/README.md
Merge pull request #50 from qiniu/develop

merge develop to master
Support callback_body option
Merge pull request #53 from GaiaMagic/master

Support callback_body option
returnUrl
Merge pull request #54 from qiniu/release/v3.4.3

callbackBody + returnUrl supported
release v3.4.4
Merge pull request #56 from why404/release/v3.4.4

release v3.4.4
ver fix
Merge pull request #57 from why404/hotfix/v3.4.5

Gemfile.lock ver fix