Use utf8 encoding

Hello @pasky!

Thanks for the speedread!

*my perl experience is next to nil* but..

I had this problem:

    ~/Applications/speedread ~/Desktop/text.txt -w 350
    #!/usr/bin/env perl
                        v
    Bytes implicitly upgraded into wide characters as iso-8859-1 at /Users/nfedyashev/Applications/speedread/speedread line 179.
                ÐºÐ¾ÑÐ¾ÑÑÐµ                                  350 wpm

and after some googling and this fix, it seems to be working now:

    ~/Applications/speedread/speedread ~/Desktop/text.txt -w 350
                        v
                       кто                                          350 wpm

    file ~/Desktop/text.txt
    /Users/nfedyashev/Desktop/text.txt: UTF-8 Unicode text, with very long lines

Probably there are better ways to fix it but it works now

HTH