`listinvoice` was not handling numeric labels correctly if they are not
passed in as JSON strings (which was the behavior of
`lightning-cli`). So now we accept both string labels as well as numeric
labels.
We need some ordering to deliver them to the JSON "waitinvoice" command;
we use a counter where 0 means "unpaid".
We keep two lists now, one for unpaid and one for paid invoices.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Christian Decker
Rusty Russell