Client certificate on the target

[cstockton]

I have a use case where I accept a https connection, and need to stitch on a client certificate for the endpoint. I tried doing something like:

      proxyOpts.target.https = {
        key: fs.readFileSync(configuration.connectKey),
        cert: fs.readFileSync(configuration.connectCert)
      }

But after some research it appears after digging through the code that you guys expect that be ONLY a bool. Is there anyway to do what I am trying to achieve? If not if I get some spare cycles and make a patch would it be accepted?

[jcrugzz]

@cstockton this is available in the new master branch. See my response in #563