Function cdt::save_debug_panic

pub fn save_debug_panic<'a, E>(
    pts: &[(f64, f64)], 
    edges: E, 
    filename: &str
) -> Result<()> where
    E: IntoIterator<Item = &'a (usize, usize)> + Copy + Clone + UnwindSafe, 

Given a set of points and edges which are known to panic, figures out the max number of save steps, then saves an SVG right before the panic occurs