[nem-en] Language support and BOM

[vc]

> I looked at the options and it seems that it doesn't have this option.
> I only found "detect utf8 without BOM".
> This is quite suprising, Eclipse also allows you to control default /
> given file encoding freely.

It's covenants de facto in Window's world. 

We can add compiler option which switches to use utf-8 as default, but by
default we should treat files without BOM as encoded in current user
encoding.