"find a tor" for client-side "tor:" endpoints

[meejah]

If a user currently uses a "tor:" client-side endpoint, it currently just tries 9050 and 9150 as SOCKS endpoints. This isn't sufficient, nor particularly safe.

What it should do instead is something like the server-side ("onion:") endpoints, and do the following:

1. if get_global_tor ever got called, use that tor we launched (adding a SOCKS port if needed)
2. try connecting to 9151 as a control-port (and ask for the SOCKS port(s))
3. try connecting to 9051 as a control port (ask for SOCKS ports)
4. call get_global_tor() ourselves, thus launching one.

[david415]

yes and if the endpoint descriptor string specifies a socks port then only that socks port should be used; here i'm thinking of people who use sandboxing to isolate various application... they might prefer an application to use a specific instance of tor.