refactor: split stuff from src/ast.rs into smaller modules

This only moves things around, to avoid huge source code modules. It
doesn't rename functions, add unit tests, or similar.

* src/datafiles.rs: DataFile, DataFiles
* src/metata.rs: Metadata
* src/panhelper.rs: functions for querying Pandoc Attrs
* src/policy.rs: the get_basedir_from function; place for later policy
  functions
* src/typeset.rs: functions to produce Pandoc AST nodes
* srv/visitor/*: various MutVisitor implementations for traversing
  ASTs, and their helper functions

1 files changed, 16 insertions, 2 deletions

diff --git a/src/lib.rs b/src/lib.rs
index c2a2ec7..842a264 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -12,9 +12,23 @@ pub use error::SubplotError;
 mod graphmarkup;
 pub use graphmarkup::{DotMarkup, GraphMarkup, PlantumlMarkup};
 
+mod datafiles;
+pub use datafiles::DataFile;
+pub use datafiles::DataFiles;
+
+mod panhelper;
+mod typeset;
+
+mod visitor;
+use visitor::LintingVisitor;
+
+mod policy;
+pub use policy::get_basedir_from;
+
+mod metadata;
+pub use metadata::Metadata;
+
 mod ast;
-pub use ast::get_basedir_from;
-pub use ast::DataFile;
 pub use ast::Document;
 
 mod scenarios;