Global code ovehaul - remove CAS and other, add 15 minute greet check

- Remove CAS, as it no longer works for us
- Remove other checks
- Implement 15 minute greet timeout check
- Fix chat logos
- Ditch thirdparty logger, use stdlib log facility wrapper for logging

internal/elog/clock.go

@@ -0,0 +1,14 @@
+package elog
+
+import "time"
+
+// nowUTC is the single clock every path and timestamp derives from.
+//
+// It is not time.Now at each call site: a log line stamped in local time beside a
+// directory named for UTC is a bug report waiting to happen, and a file that rolls
+// over at midnight local time while its lines are stamped UTC is worse.
+func nowUTC() time.Time {
+	return time.Now().UTC()
+}
+
+/* vim: set ft=go noet ai ts=4 sw=4 sts=4: */