Make saturnin__version() smarter

Only print tagline if defined (similar to codename); do not make it up
with silly string.

Also we can do away without any local variables *and* very safely inside
79 character width recommendation.

src/saturnin.sh.skel

     #
     # Print version info
     #
-    local tagline=${SATURNIN_APP_TAGLINE:-Some app with default tagline}
-    local maybe_codename=""
-    test -n "$SATURNIN_APP_CODENAME" && maybe_codename=" - $SATURNIN_APP_CODENAME"
-    echo "$(basename "$0") ($tagline) $SATURNIN_APP_VERSION$maybe_codename"
+    echo -n "$(basename "$0")"
+    test -n "$SATURNIN_APP_TAGLINE" \
+     && echo -n " ($SATURNIN_APP_TAGLINE)"
+    echo -n " $SATURNIN_APP_VERSION"
+    test -n "$SATURNIN_APP_CODENAME" \
+     && echo -n " - $SATURNIN_APP_CODENAME"
+    echo
     return "$EXIT_OK"
 }