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 
To expand on that: ANSI_X3.110-1983 is close to ISO-8859-1, but is not equivalent. Fuzzy/almost matching won't fly.