Windows cert verify improvements + leak fixes

- Clean up properly at all fail points in native Windows peer
  verification routine
- Bring certificate usages and chain flags into line with chromium
  implementation in windows environments
Capture peer cert even if verify fails

Previously the "capture_peer_cert" SSL context option only
captured the peer's certificate if the verification routine
succeeded.

By also capturing the on verify failure applications have the
ability to parse the cert and ask users whether they wish to
proceed given the information presented by the peer.