Show markdown syntax with roff markup.
Require kramdown for the specs.
Avoid using \&.
Began adding specs for Converter.
Revert "Avoid using \&."

This reverts commit 70033b66e737228c9db63acc4969d6fac56435d7.
Distinguish between [text](mailto:email) and <email> in convert_a.
Fixed the man: regex in convert_a.
Add an extra \n before the .MT tag.
Added specs for convert_a.