Add newlines to ghc-mod's info command.

When running `ghc-mod info`, each line is separate by '\0' by default.
(This may have been added in ghc-mod version 4.0.)

I have added the `--boundary "\n"` flag in order to make all of the info
provided by the `ghc-mod info` command actually show up in the :echo
done by vim.

Without this flag, it looks like the output is getting cut off at the
first '\0'.
Merge pull request #51 from cdepillabout/add-newlines-to-ghc-mod-info

Add newlines to ghc-mod's info command.