Merge pull request #2 from qiniu/develop

Release v0.5.0
rs unit test
Merge pull request #15 from pipul/feature/b_fd_rs_ut2

rs unit test
remove encodeuri
init
remove auto delete
update
update by review
Merge pull request #18 from chzyer/feature/update_by_spec

Feature/update_by_spec
update
update
update that allow dntoken equals with ""
remove test put file
fix bugs
bugs fix
fix bugs that catch error
fix bugs close PipeReader
update
update
Merge pull request #17 from chzyer/feature/add_io

Feature/add_io