CLI: return ZINT_ERROR_INVALID_OPTION instead of 1 on bad option and

ZINT_WARN_INVALID_OPTION instead of 0 on ignored option;
  more barcode synonyms
manual: append man page zint.1.pmd instead of CLI help;
  various tweaks and fiddlings;
  rMQR add ISO 23941 (released the other day but haven't got yet)
man page: expand and tweak
doc/Makefile: add HTML demo

docs/inc_header_pdf.tex

@@ -13,7 +13,7 @@
 %% https://github.com/jgm/pandoc/wiki/Pandoc-Tricks#definition-list-terms-on-their-own-line-in-latex
 \let\originalitem\item
 \makeatletter
-\renewcommand{\item}[1][\@nil]{
+\renewcommand{\item}[1][\@nil]{%
     \def\tmp{#1}
     \ifx\tmp\@nnil\originalitem\else\originalitem[#1]\hfill\par\fi}
 \makeatother
@@ -27,7 +27,7 @@
 %% Unfortunately this messes up wrapping TODO: fix
 %% Background color for inline code https://tex.stackexchange.com/a/507116
 %\definecolor{icbg}{HTML}{fafafa} % Same as modified pygments.theme
-%\newcommand{\code}[1]{
+%\newcommand{\code}[1]{%
     %\begingroup\setlength{\fboxsep}{1pt}
     %\colorbox{icbg}{\oldtexttt{\hspace*{0.1pt}\vphantom{A}#1\hspace*{0.1pt}}}\endgroup}
 %\renewcommand{\texttt}[1]{\textcolor{icfg}{\code{\oldtexttt{#1}}}}