NAME
        DeleteLayer -- delete layer from layer list.

    SYNOPSIS
        result = DeleteLayer( dummy, l )
        d0                    a0,    a1

        long deletelayer( long, struct layer *);

    FUNCTION
        remove this layer from the list of layers.  release memory
        associated with it.  Restore other layers that may have been
        obscured by it.  Trigger refresh in those that may need it.
        If this is a superbitmap layer make sure SuperBitMap is current.
        The SuperBitMap is not removed from the system but is available
        for program use even though the rest of the layer information has
        been deallocated.

    INPUTS
        dummy - unused
        l - pointer to a layer

    RESULTS
        result - TRUE if this layer successfully deleted from the system
                 FALSE if layer not deleted. (probably out of memory )

    BUGS

    SEE ALSO
        graphics/layers.h, graphics/clip.h