tls: guard against faulty gemini servers Some gemini servers have faulty TLS handling, such as: gg: tls_close: EOF without close notify In such cases, telescope will receive that error and naturally assume there was a problem and stop processing. However, in the case of there still being legitimate content read from the request, this should still be displayed, rather than ignored. This change therefore detects this condition and adds a status of 'W' to telescope's modeline to indicate that the information presented is from a faulty gemini server and could be truncated and hence display oddly.

move imsgev & co to their own file This avoids bringing the dependency on ev on telescope-identity(1) and the tests as well.