FindTheorems performance improvements (from Timothy Bourke)
* Prefilter the list of theorems based on the constants and
free variables in Pattern search terms, before calling
Pattern.matches_subterm.
* Apply filters successively rather than running each and
then finding the intersection.
* Show the time taken to run a query.
\railalias{percent}{\%}
\railalias{ppercent}{\%\%}
\railalias{underscore}{\_}
\railalias{lbrace}{\texttt{\ttlbrace}}
\railalias{rbrace}{\texttt{\ttrbrace}}
\railalias{atsign}{{\at}}
\setlength\railextra{3.6ex}
\setlength\railboxleft{0.9ex}
\setlength\railboxright{0.9ex}
\setlength\railovalspace{1.8ex}
\setlength\railframespace{1.8ex}
\setlength\railtextleft{0.9ex}
\setlength\railtextright{0.9ex}
\setlength\railnamesep{0.9ex}
\setlength\railboxheight{16pt}
\setlength\railboxskip{24pt}
\setlength\railtextup{5pt}
\setlength\railjoinsize{16pt}
\def\rail@termfont{\small\ttfamily\upshape}
\def\rail@tokenfont{\small\ttfamily\upshape}
\def\rail@nontfont{\small\rmfamily\upshape}
\def\rail@annofont{\small\rmfamily\itshape}
\def\rail@namefont{\small\rmfamily\itshape}
\def\rail@indexfont{\small\rmfamily\itshape}
\newcommand{\railtterm}[1]{{\texttt{#1}}}
\newcommand{\railtok}[1]{{\textrm{#1}}}
\newcommand{\railqtok}[1]{{\rmfamily\textsl{#1}}}
\newcommand{\railnonterm}[1]{{\emph{#1}}}