Refactoring code.
Rename Pi0PathSpace to Pi0Paths
Minor refactoring in SplitCode.agda.
Delete outdated comments.
Add trans-to (nondep funs) and concat-ap.
Add to-is-set.
Rename trans-glue to trans-code-glue.
Improve Pi0Paths.agda.
Make C and CF private in Code.agda.
Remove duplicate code.