Mandatory exercise errata

The first page of the mandatory exercise refers to a computer-readable version of the distance table in the pickles file format.  This is not availible, since I have no experience with the format, but the sentence snuck into the text.  I apologise for any confusion this may have caused. The table is still availible in a nice tab-separated plaintext file, which should be easily parseable by your favorite programming language (think input.readLine().split("\t")). -E