[styles,macros] Improve automatic page breaking

 - Strongly discourage breaking between itemdecl and itemdescr.
 - Mildly discourage breaking inside an itemdecl.
 - Encourage breaking after a codeblock.
 - Encourage breaking at empty lines in a codeblock.
 - Encourage breaking after a semicolon or closing brace.
 - Mildly discourage breaking before an itemized list.
 - Allow substantial whitespace at the end of a page.

Author: jensmaurer

source/layout.tex

@@ -18,6 +18,12 @@
 \setmarginnotes{7pt}{7pt}{0pt}
 \checkandfixthelayout
 
+%%--------------------------------------------------
+%% If there is insufficient stretchable vertical space on a page,
+%% TeX will not properly consider penalties for a good page break,
+%% even if \raggedbottom (default) is in effect.
+\addtolength{\topskip}{0pt plus 20pt}
+
 %%--------------------------------------------------
 %% Paragraph and bullet numbering
 

source/macros.tex

@@ -348,7 +348,9 @@
 % italics.  Arbitrary TeX commands can be used if they're
 % surrounded by @ signs.
 \newcommand{\CodeBlockSetup}{
- \lstset{escapechar=@, aboveskip=\parskip, belowskip=0pt}
+ \lstset{escapechar=@, aboveskip=\parskip, belowskip=0pt,
+         midpenalty=500, endpenalty=-50,
+         emptylinepenalty=-250, semicolonpenalty=0}
  \renewcommand{\tcode}[1]{\textup{\CodeStylex{##1}}}
  \renewcommand{\techterm}[1]{\textit{\CodeStylex{##1}}}
  \renewcommand{\term}[1]{\textit{##1}}
@@ -381,6 +383,9 @@
 {
  \lstset{escapechar=@,
  xleftmargin=0em,
+ midpenalty=500,
+ semicolonpenalty=-50,
+ endpenalty=3000,
  aboveskip=2ex,
  belowskip=0ex	% leave this alone: it keeps these things out of the
 				% footnote area
@@ -391,7 +396,7 @@
 
 \newenvironment{itemdescr}
 {
- \begin{indented}}
+ \begin{indented}[beginpenalty=3000, endpenalty=-300]}
 {
  \end{indented}
 }

source/styles.tex

@@ -103,7 +103,8 @@
 \setlength{\partopsep}{0pt}
 \newlist{indenthelper}{itemize}{1}
 \newlist{bnflist}{itemize}{1}
-\setlist[itemize]{parsep=\parskip, partopsep=0pt, itemsep=0pt, topsep=0pt}
+\setlist[itemize]{parsep=\parskip, partopsep=0pt, itemsep=0pt, topsep=0pt,
+                  beginpenalty=10 }
 \setlist[enumerate]{parsep=\parskip, partopsep=0pt, itemsep=0pt, topsep=0pt}
 \setlist[indenthelper]{parsep=\parskip, partopsep=0pt, itemsep=0pt, topsep=0pt, label={}}
 \setlist[bnflist]{parsep=\parskip, partopsep=0pt, itemsep=0pt, topsep=0pt, label={},