fix section titles (they were not appearing), bug introduced by #66

TimesAPriori_MIT.cls

@@ -750,7 +750,7 @@ ItalicFont=SyntaxLTStd-Italic,
     \begingroup
       #6{%
         \@hangfrom{\hskip #3\relax\@svsec}%
-          \interlinepenalty \@M \titlecap[\sansbold{#8}] \@@par}%
+          \interlinepenalty \@M \titlecap{\sansbold{#8}} \@@par}%
     \endgroup\else
     \begingroup
       #6{%

book.tex

@@ -1,6 +1,4 @@
-%\documentclass[]{TimesAPriori_MIT}%%6x9
 \documentclass[7x10]{TimesAPriori_MIT}%%7x10
-%\documentclass[8x10]{TimesAPriori_MIT}%%8x10
 
 \usepackage[utf8]{inputenc}
 %% \usepackage{setspace}
@@ -6303,7 +6301,7 @@ for some operations we are more restrictive, for example, rejecting
 This chapter is organized as follows.  We begin by defining the syntax
 and interpreter for the \LangIf{} language
 (Section~\ref{sec:lang-if}). We then introduce the idea of type
-checking and build a type checker for \LangIf{}
+checking and define a type checker for \LangIf{}
 (Section~\ref{sec:type-check-Lif}).
 %
 \racket{To compile \LangIf{} we need to enlarge the intermediate