fix Makefile
Makefile updates darcs-hash:20090128210704-5007d-a897836dbabcc2ed906a3e2dd7ddbeee36db8e3c.gz
checkpoint darcs-hash:20080629044727-5007d-82e649c22f31951011423bd8123d5cafcfb6a538.gz
add RTree classes darcs-hash:20071214015317-5007d-31f9de5bc2afdc9cade724105114fec68e940c5b.gz
checkpoint darcs-hash:20071206001213-5007d-a802d227af2ef608c566c45a29331a2923b510c1.gz
checkpoint darcs-hash:20071205040722-5007d-97201547773e464dbcd363718ed6f2a518a3b6f8.gz
switched to true half-edge darcs-hash:20071202004440-5007d-e41543f8fb19a225ae1dd76a4309240920415efe.gz
checkpoint darcs-hash:20071126035054-5007d-07a55acc220977fa3a8c23eb9e061296e1fca9e6.gz
init darcs-hash:20071126034357-5007d-538cebe4569498197ec1e1a53f79348b55540f15.gz