Extent calculation in Asymptote graphs is faulty

[rocky]

Recently in #1498 Arcs were extended to handle elipses. However calculating their proper size is still missing.

In particular the extent calculation for:

Graphics[{Blue, Disk[{0, 0}, {1, 2}, {Pi / 3, 5 Pi / 3}]}]

doesn't adjust for the elliptic behavior. This is not isolated new case.

In fact if you the manual you'll see lots examples.

Graphics[{Circle[{0, 0}, 1]}] (* This one is subtle. The top and bottom boundary is truncated. *)
Table[
  Graphics[
     {Circle[], 
       Arrow[Table[{Cos[phi],Sin[phi]},{phi,0,2*Pi,Pi/2}],{d, d}]
     }],
   {d,0,2,0.5}]  (* Probably we need to adjust for Table *)
Graphics[
   {Arrowheads[
     Table[
        {0.04, i/10, Graphics[Disk []]},{i,1,10}
       ] ], 
    Arrow[{{0, 0}, {6, 5}, {1, -3}, {-2, 2}}
    ]}
 ]