Switch to a DocumentFragment for to_html
Use a single cached XML::Document instead of creating them all over
Introduce shorthand for creating XML elements and text nodes
Clean up lib/maruku/output/to_html.rbx
Basic indentation and whitespace for lib/maruku/output/to_latex.rb
Clean up lib/maruku/output/to_latex.rb
 Fix errors in IAL parsing

These didn't used to cause an error.

I think it's OK to hit an EOF in these
cases. So we don't call that an error.