super single or multiple terms on labeled list
resolves #486 add docinfo option for footer
Merge pull request #553 from mojavelinux/docinfo-footer

resolves #486 add docinfo option for footer
optimizations and cleanups

- use constant for endline
- use string template for dlist
- store toc lines in array, then join
- add test for strong option on horizontal list
- join rendered blocks on endline