Add newline transcoders.

For future reference: MRI appears to generate newline.c, the
transcoder logic and data, into the root of the Ruby source tree.
As a result, our scripts did not find it. I moved the .c file and
ran the scripts, but future updates will need to this or something
like it.
Add some flags used for IO (not yet though).
Fix decorating logic and universal_newline replacement.