Store the reference httpServer in tern server instance
Store the reference httpServer in tern server instance

This PR gives the capability to retrieve by a tern plugin the httpServer from the server server instance. See discussion at https://github.com/ternjs/tern/issues/679

In my case I need that to use tern with WebSocket to send to the client when Angular modules changes. I'm developping a generic project which provides a new method to the tern server sendToClient in https://github.com/angelozerr/tern-push

eranif/tern,eranif/tern,eranif/tern