Handle org-mode documents passed as args.

We were running into issues where the documents grew too large for being passed as a string to emacs, and we need to handle #+setupfile so we need to start handling org-mode documents as files and not just as anonymous streams of text.

The anonymous stream of text handling will remain because the automated tests use it.

src/compare/mod.rs

@@ -2,6 +2,7 @@ mod diff;
 mod parse;
 mod util;
 pub use diff::compare_document;
-pub use parse::emacs_parse_org_document;
+pub use parse::emacs_parse_anonymous_org_document;
+pub use parse::emacs_parse_file_org_document;
 pub use parse::get_emacs_version;
 pub use parse::get_org_mode_version;