Added \VerbatimFootnotes if there is verbatim in notes.

See http://tex.stackexchange.com/questions/203/how-to-obtain-verbatim-text-in-a-footnote

Closes jgm/pandoc#1616.

default.latex

@@ -70,6 +70,7 @@ $highlighting-macros$
 $endif$
 $if(verbatim-in-note)$
 \usepackage{fancyvrb}
+\VerbatimFootnotes
 $endif$
 $if(tables)$
 \usepackage{longtable,booktabs}