Make xubuntu minimal a subproject

debian/tests/default-bootstraps

@@ -39,7 +39,7 @@ ALL_TRIPLETS="
  ubuntu-netbook::
  ubuntu-server:live:ubuntu-server
  xubuntu::
- xubuntu-minimal::"
+ xubuntu:minimal:"
 
 if [ -z "$SELECTED_TRIPLETS" ]; then
     SELECTED_TRIPLETS="

live-build/auto/config

@@ -656,7 +656,7 @@ case $PROJECT in
 	kubuntu|kubuntu-dvd|kubuntu-plasma5|ubuntu-gnome|ubuntu-budgie|ubuntukylin)
 		COMPONENTS='main restricted universe'
 		;;
-	xubuntu|xubuntu-minimal|mythbuntu|lubuntu|ubuntu-mate|ubuntu-unity|ubuntustudio-dvd|ubuntu-unity)
+	xubuntu|mythbuntu|lubuntu|ubuntu-mate|ubuntu-unity|ubuntustudio-dvd|ubuntu-unity)
 		COMPONENTS='main restricted universe multiverse'
 		;;
 esac
@@ -776,16 +776,14 @@ case $PROJECT in
 		;;
 
 	xubuntu)
+		case ${SUBPROJECT:-} in
+			minimal)
+				add_task install minimal standard xubuntu-desktop-minimal
+				;;
+			*)
 				add_task install minimal standard xubuntu-desktop
-		add_package install xterm
-		LIVE_TASK='xubuntu-live'
-		case $ARCH in
-			amd64)	KERNEL_FLAVOURS=generic ;;
-		esac
 				;;
-
+		esac
-	xubuntu-minimal)
-		add_task install minimal standard xubuntu-desktop-minimal
 		add_package install xterm
 		LIVE_TASK='xubuntu-live'
 		case $ARCH in