From: Intransition <transfire@...>
Date: 2010-11-02T04:27:28+09:00
Subject: Standard Base62 Encoding?

Is there a standard encoding for base62? I've been using 0..9a..zA..Z,
but I think I should switch that to 0..9A..Za..z, so it would sort
properly according to ASCII order. I wasn't able to find anything on a
standard via a Google search. So maybe there just isn't one?

I was kind of surprised to see Ruby uses lower case a..f for
hexadecimal rather than uppercase.

  "255.to_s(16)  #=> "ff"