I'm not sure where the BOM came from, originally.
http://www.gutenberg.org/files/74/74.txt doesn't have it, although
a fresh download of that URL gives me "\r\n"s instead of plain "\n"s,
and the extra line "Character set encoding: ASCII". Maybe Project
Gutenberg has changed their server configuration since we added that
file to the Go repo.

Anyway, this change is just manually excising the BOM from the start
of the file, leaving pure ASCII.

R=r, bradfitz
CC=golang-dev, krasin, rsc
https://golang.org/cl/6197061