Text background - the right argument uses format ["text","type",speed] or ["text","type"].
If speed is not given, it is assumed to be one.
Type may be one of:
"PLAIN",
"PLAIN DOWN",
"BLACK",
"BLACK FADED",
"BLACK OUT",
"BLACK IN",
"WHITE OUT","
WHITE IN".
The left argument defines the layer in which the effect is shown, 0 is the back most.