%% links

\def\link#1{%
  \penalty-500%
  \pdfstartlink
    user{/Subtype /Link
    /Border [ 0 0 0 ]
    /A <<
      /Type /Action
      /S /URI
      /URI (#1)
    >>}%
    {\tt \color{blue} #1}%
  \pdfendlink
}

%% the godly `pre`

\def\pre#1{\par\leavevmode\llap{\hbox to \parindent{\hfil #1 \hfil}}}

%% gives image files surrounding stretch
\newskip\imgskipamount
\def\imgskip{\vskip\imgskipamount}
\imgskipamount=0pt plus 48pt
\def\image #1 {\imgskip\input #1\imgskip}