Merge pull request pili-engineering#25 from hzwangsiyu/master

update podspec

update podspec

update podspec

v2.1.1 release

Merge pull request pili-engineering#4 from hzwangsiyu/master

v2.1.0 beta release

Merge pull request pili-engineering#1 from hzwangsiyu/master

v2.0.0 release