Merge pull request #1 from chank/master

Add test cases
Check the MyException
Merge branch 'master' of github.com:Atry/stateless-future-util
Add SocketInputStream.duplicate
Adjust format
Fix the wrong comment about IllegalStateException
把Promise移到stateless-future-util
增加SleepFuture功能
Delete unused println
Rename SleepFuture to Sleep
Replace Interruptor with Poll
Remove unsed type parameter `That`
Fix scaladoc reference
Add move method instead of duplicate
Remove the println
Release 0.4.0
Bump version
Update version in README.md
Update README.md
Update README.md