more encodings and their equivalents

our users use a bunch of things ruby does not support, after a bit of googling most of them are very similar to ISO_8859-X

not sure if there is a better place for there tests ...

@bf4 @jeremy 
the other encoding methods catch encoding errors and force-convert to utf-8, so we end up with an even worse corruption ... https://github.com/mikel/mail/blob/master/lib/mail/version_specific/ruby_1_9.rb#L85-L87