Update our preferences logic to get the first returned matching

preference and to allow submenu preferences, like the program size for
teensy variants.

I -believe- this will work on macOS, but need to test.

etc/kaleidoscope-builder.conf

@@ -60,7 +60,7 @@ find_device_vid_pid() {
 get_arduino_pref() {
 	pref=$1
 	# Strip the preference name. And then strip leading and trailing quotations
-	MESSAGE=$(dump_arduino_prefs | grep ${pref}= | sed -e s/^${pref}=// -e 's/^"//' -e 's/"$//')
+	MESSAGE=$(dump_arduino_prefs | grep --max-count=1 ${pref}= | sed -e s/^.*${pref}=// -e 's/^"//' -e 's/"$//')
 	echo $MESSAGE
 }