Since commit ed1ea24c (Fix INSERT to allow inserting to empty list,
2006-05-15) the list command allows insertion into an empty list at
index 0. Fix rejection of insertion at non-zero (negative) indices to
present an error message instead of crashing.
While at it, fix the error message of the GET and REMOVE_AT operations
when the list is empty to not present a bogus allowed range.
Add a "RunCMake.list" test to cover failure cases on empty lists.
Brad King