Data.ByteString candidate 4

Ok, I've tried to encorporate the suggestions from yesterday's
discussion.

API: http://www.cse.unsw.edu.au/~dons/fps/new/
Src: http://www.cse.unsw.edu.au/~dons/fps.html
    
Changes:
    * Char functions live in Data.ByteString.Char8
    * Improved docs
    * Anything that needs Data.Char is now in Char8 (lines, words..)
    * Confirmed that Char8 runs at the same speed as the Word8 layer
    * isSuffix is about 100x faster.
    
No claims about being a 'Char' packed string library. Don't make claims about
encodings. Char8.hs is just a no-op layer over the underlying Data.ByteString
Word8 ops.

I'm wary of claiming 'PackedString' status, as John says, it isn't a
drop in replacement, so Data.ByteString.Char8 seems fine to me.

-- Don