[fix] Manage bookkeeping for incoming requests to the underlying sockets behind reverse proxied websocket events. Only use the appropriate variables in the closure scope of the `upgrade` event from this bookkeeping

This reverts commit 642e1580.

Looks like this may fix the issue that I reported

[doc api] Update README.md and CHANGELOG.md for v0.5.0. Update bin/node-http-proxy to read files specified in `config.https`

[api] Update `.proxyRequest()` and `.proxyWebSocketRequest()` APIs to take an options hash instead of a set of arguments. Add HTTPS support.

[api] Update `request` event to be consistent by emitting both `req` and `res`. Add `x-forwarded-for` header.

[doc api test] Wrap things up for v0.4.0 release: Add hostnameOnly routing to ProxyTable, add more documentation, fix edge-cases until they can be further investigated in node.js core

[doc api test] Rename HttpProxy.pause to HttpProxy.resume. Update documentation and tests accordingly