allow setting a custom converter

I'm mostly working on inbound mail and I need to do a lot of guessing / non-perfect conversions that are a little to buggy for to integrate here, having this api would allow me to throw away a bunch of monkeypatches.

@bf4 @jeremy @mikel 


with classes both patterns work / user can choose, modules give us nothing
...


On Tue, Aug 26, 2014 at 9:15 PM, Benjamin Fleischer <
notifications@github.com> wrote:

> In lib/mail/version_specific/ruby_1_9.rb:
>
> > @@ -2,6 +2,72 @@
> >
> >  module Mail
> >    class Ruby19
> > +    class SimpleConverter
> > +      class << self
> > +        def convert(string, charset)
>
> As tenderlove once tweeted "I knew a guy who preferred inheritance over
> composition. He was a 'super' guy".
>
> Wouldn't composition be a better pattern? The test you wrote implies
> replacing the converter, rather than extending it.
>
> I don't feel strongly if there's a good use-case for inheritance.
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/mikel/mail/pull/785/files#r16756746>.
>