line endings

[ggrothendieck]

One has to use this on Windows in order to use other utilities that expect standard Windows clrf line endings

xsv fmt --crlf

but use this on other systems:

xsv fmt 

This makes it difficult to write cross platform code. A flag that gives the native line endings for that platform and a flag that outputs whatever line endings are input would be nice or maybe one of those should be the default.