Get rid of appendToBody and introduce appendTo

[greendrake]

Flexibility is needed as to where exactly the list gets appended to. Having only two options (to the body and right after the main element) is not enough.

The need to append the list somewhere else arose from this case where I needed to render the list inside a scrollable div within a <dialog> element. The list would hide behind the boundary of the scrollable div. To make it visible I had to append it to the dialog element directly.

This PR proposes getting rid of the appenToBody boolean and replacing it with a more general appendTo property. Seems like a breaking change, but hey, this is the next major.