update introduction and about

Merge pull request #33 from beeth0ven/release/2.0.0

Release/2.0.0

Merge branch 'master' of https://github.com/beeth0ven/RxSwift-Chinese…

…-Documentation

fix typos

Update to RxSwift 4.0.0

Release 0.2.0

Publish 0.1.1

Add Hot and Cold Observables Link

Add Change Log