Changes the way clients are created slightly:
 - (slightly, ostensibly) better performance when one knows if they want
   a secure connection or not. This means no match statement redirecting
   calls to their respective SSL or TCP stream.
   These calls have been named:
    - `connect` for insecure connections
    - `connect_secure` for secure connections

 - If one does not know how which connection it wants it can take the
   (not verified by testing) performance hit of putting the underlying
   stream on the heap behind a `Box`. This can be done with:
    - `connect_agnostic`

All calls currently take the custom ToWebSocketUrlComponents but that
should be changed to a `Url` (probably from rust-url).

The last bit is to extract the NetworkStream from a hyper server-side
request and save that as a Stream, then turn it into an Incoming<(..)>
and validate the request.

Implementing Stream for a NetworkStream is proving complicated, since
because now there is conflicting implementations for many structs
implementing NetworkStream.

…re all AsTcpStreams implement Stream

This was initially very hard because one cannot clone unsized types and
put them on the stack. I was about to revert to WebSocketStream style
enum-variant-per-sized-type style but I managed to live another day
without all those match blocks.

The validation is done, now the only work is to extract the underlying
stream.

… protocols, etc.

this is possible with the help of hyperium/hyper#1107