logging: make -verbose -termui=false log to stdout

Commit d72563ac30bab6471121f561f3bb41991a3c91d1 made it so we never send
logs to stdout/stderr, but I prefer them on stderr when possible. So, if
termui isn't enabled, let's send them to stderr. --termui used to not be
propogated; now it is.
diff --git a/dockerimg/dockerimg.go b/dockerimg/dockerimg.go
index 41026a4..d824dd0 100644
--- a/dockerimg/dockerimg.go
+++ b/dockerimg/dockerimg.go
@@ -101,6 +101,9 @@
 
 	// ExperimentFlag contains the experimental features to enable
 	ExperimentFlag string
+
+	// TermUI enables terminal UI
+	TermUI bool
 }
 
 // LaunchContainer creates a docker container for a project, installs sketch and opens a connection to it.
@@ -490,6 +493,7 @@
 		"-outside-os="+config.OutsideOS,
 		"-outside-working-dir="+config.OutsideWorkingDir,
 		"-open=false",
+		"-termui="+fmt.Sprintf("%t", config.TermUI),
 		"-x="+config.ExperimentFlag,
 	)
 	if config.Model != "" {