Re: ack may ignore files with multi-byte encodings

I think my one-line change to Basic.pm solves the problem I pointed out.  It does for me (obviously) and doesn't hurt the existing tests.

I haven't been able to make up a specific test for the rejection of multibyte-encoded files with the given testing framework.  There seem to be additional encoding problems that make it hard to use run_ack() for that.  So I'm just sending the fix.

Anno