Track dependencies of Asymptote files

[Feuermurmel]

Maybe we have to do this by parsing the output of asy -vv:

michi .../src/shapes$ asy -vv rainbow_dash_small_stamp.asy 
Using configuration directory /Users/michi/.asy
Welcome to Asymptote version 2.35
cd /users/michi/Desktop/3D/Designs/Stempel/src/shapes
Processing rainbow_dash_small_stamp
Loading plain from /opt/local/share/asymptote/plain.asy
Including plain_constants from /opt/local/share/asymptote/plain_constants.asy
Loading version from /opt/local/share/asymptote/version.asy
Including plain_strings from /opt/local/share/asymptote/plain_strings.asy
Including plain_pens from /opt/local/share/asymptote/plain_pens.asy
Including plain_paths from /opt/local/share/asymptote/plain_paths.asy
Including plain_filldraw from /opt/local/share/asymptote/plain_filldraw.asy
Including plain_margins from /opt/local/share/asymptote/plain_margins.asy
Including plain_picture from /opt/local/share/asymptote/plain_picture.asy
Loading plain_scaling from /opt/local/share/asymptote/plain_scaling.asy
Loading simplex from /opt/local/share/asymptote/simplex.asy
Loading plain_bounds from /opt/local/share/asymptote/plain_bounds.asy
Including plain_scaling from /opt/local/share/asymptote/plain_scaling.asy
Including plain_prethree from /opt/local/share/asymptote/plain_prethree.asy
Including plain_Label from /opt/local/share/asymptote/plain_Label.asy
Including plain_shipout from /opt/local/share/asymptote/plain_shipout.asy
Including plain_xasy from /opt/local/share/asymptote/plain_xasy.asy
Including plain_arcs from /opt/local/share/asymptote/plain_arcs.asy
Including plain_boxes from /opt/local/share/asymptote/plain_boxes.asy
Including plain_markers from /opt/local/share/asymptote/plain_markers.asy
Including plain_arrows from /opt/local/share/asymptote/plain_arrows.asy
Including plain_debugger from /opt/local/share/asymptote/plain_debugger.asy
Loading rainbow_dash_small_stamp.asy from rainbow_dash_small_stamp.asy
Loading _stamp from _stamp.asy
Loading stamps from stamps.asy
Wrote rainbow_dash_small_stamp.eps