Ajson-rpc2

- Add pip install support, the package is publish on pip now :)

- Introduce Module feature, so ajson-rpc2 can support for method like "document/open", "window/open", "foo.bar", "foo.bar2"

Added
- Add Support to define the behavior of rpc call, so we can make rpc called in another process

Added
- Support batch request / response
- Add acceptance tests for ajson-rpc2

Added
- Make everything keep alive. Which is support basic json rpc2 protocol