update version with appropriate tag

add document

Merge branch 'master' of https://github.com/websocket-client/websocke…

…t-client

update document for wsaccel

fixed websocket-client#327

revert websocket-client#301

fixed websocket-client#325

fixed websocket-client#274

update document and set version to 0.40!

!

fix classifier

release v0.37