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/mylog/standard.go

@@ -0,0 +1,28 @@
+package mylog
+
+// The standard-library-compatible Logger: what a module receives instead of
+// depending on *log.Logger itself, and where its messages end up.
+
+import "strings"
+
+// Standard returns the Logger for modules that would otherwise depend on the
+// standard library's *log.Logger. Messages passed to it are logged at debug
+// level into the already-open destination.
+//
+// Returning the interface rather than the concrete *adapter is the whole point:
+// it is the type such modules declare, so hiding it would defeat the
+// substitution it exists for.
+func Standard() Logger { //nolint:ireturn // deliberate public interface
+	return standard
+}
+
+// Output implements Logger, logging at debug level. The trailing newline of the
+// standard library convention is trimmed so that mylog does not append a blank
+// line to every message.
+func (a *adapter) Output(_ int, s string) error {
+	write(levelDebug, strings.TrimRight(s, "\r\n"))
+
+	return nil
+}
+
+/* vim: set ft=go noet ai ts=4 sw=4 sts=4: */