Change ulem to lua-ul; refs ftilmann#277

This hack just changes in the DATA section:

ulem -> lua-ul
[normalem] ->
\sout -> \strikeThrough
\uwave -> \underLine

When this is used, output must be compiled with lualatex.

Some thoughts on implementing this in upstream latexdiff:

1. To make this an actual option, instead of hardcoding this change,
one would probably want to make general commands that call the right
ulem or lua-ul commnad, with separate preamble sections for either
ulem:

\RequirePackage[normalem]{ulem}
\newcommand[1]{\DIFstrikethrough}{\sout{ftilmann#1}}
\newcommand[1]{\DIFunderline}{\uwave{ftilmann#1}}

or lua-ul

\RequirePackage{lua-ul}
\newcommand[1]{\DIFstrikethrough}{\strikeThrough{ftilmann#1}}
\newcommand[1]{\DIFunderline}{\underLine{ftilmann#1}}

and then could make these changes instead

\RequirePackage[normalem]{ulem} ->
\sout -> \DIFstrikethrough
\uwave -> \underLine

This, however, would require adding in the logic to have either lua-ul or ulem into
the code.

I also hope the indirection like this won't break some LaTeX macro
somewhere but can't be sure of that.

Other options I considered would be:
- duplicating all these sections to have a ulem and a lua-ul
version (yuck)
- searching for these words and replacing them when reading in
preamble sections (D:)
- simply eliminating ulem support (working around it certainly seems to have caused a
lot of headaches for the creators of latexdiff)

2. lua-ul doesn't have the capacity out of the box to produce wavy
underlines like ulem, but is very configurable and it could be added.
Instructions are even in the lua-ul manual.

latexdiff

@@ -5338,10 +5338,10 @@ verbatim[*]?
 %%% TYPES (Commands for highlighting changed blocks)
 
 %DIF UNDERLINE PREAMBLE
-\RequirePackage[normalem]{ulem}
+\RequirePackage{lua-ul}
 \RequirePackage{color}\definecolor{RED}{rgb}{1,0,0}\definecolor{BLUE}{rgb}{0,0,1}
-\providecommand{\DIFadd}[1]{{\protect\color{blue}\uwave{#1}}}
-\providecommand{\DIFdel}[1]{{\protect\color{red}\sout{#1}}}                     
+\providecommand{\DIFadd}[1]{{\protect\color{blue}\underLine{#1}}}
+\providecommand{\DIFdel}[1]{{\protect\color{red}\strikeThrough{#1}}}                     
 %DIF END UNDERLINE PREAMBLE
 
 %DIF CTRADITIONAL PREAMBLE
@@ -5367,10 +5367,10 @@ verbatim[*]?
 %DIF END CFONT PREAMBLE
 
 %DIF FONTSTRIKE PREAMBLE
-\RequirePackage[normalem]{ulem}
+\RequirePackage{lua-ul}
 \DeclareOldFontCommand{\sf}{\normalfont\sffamily}{\mathsf}
 \providecommand{\DIFadd}[1]{{\sf #1}}
-\providecommand{\DIFdel}[1]{{\footnotesize \sout{#1}}}
+\providecommand{\DIFdel}[1]{{\footnotesize \strikeThrough{#1}}}
 %DIF END FONTSTRIKE PREAMBLE
 
 %DIF CCHANGEBAR PREAMBLE
@@ -5388,11 +5388,11 @@ verbatim[*]?
 %DIF END CFONTCHBAR PREAMBLE
 
 %DIF CULINECHBAR PREAMBLE
-\RequirePackage[normalem]{ulem}
+\RequirePackage{lua-ul}
 \RequirePackage[pdftex]{changebar}
 \RequirePackage{color}\definecolor{RED}{rgb}{1,0,0}\definecolor{BLUE}{rgb}{0,0,1}
-\providecommand{\DIFadd}[1]{\protect\cbstart{\protect\color{blue}\uwave{#1}}\protect\cbend}
-\providecommand{\DIFdel}[1]{\protect\cbdelete{\protect\color{red}\sout{#1}}\protect\cbdelete}
+\providecommand{\DIFadd}[1]{\protect\cbstart{\protect\color{blue}\underLine{#1}}\protect\cbend}
+\providecommand{\DIFdel}[1]{\protect\cbdelete{\protect\color{red}\strikeThrough{#1}}\protect\cbdelete}
 %DIF END CULINECHBAR PREAMBLE
 
 %DIF CHANGEBAR PREAMBLE
@@ -5677,8 +5677,8 @@ verbatim[*]?
 %DIF END COLORLISTINGS PREAMBLE
 
 %DIF DIFCODE_UNDERLINE
-  moredelim=[il][\color{red}\sout]{\%DIF\ <\ },
-  moredelim=[il][\color{blue}\uwave]{\%DIF\ >\ }
+  moredelim=[il][\color{red}\strikeThrough]{\%DIF\ <\ },
+  moredelim=[il][\color{blue}\underLine]{\%DIF\ >\ }
 %DIF END DIFCODE_UNDERLINE
 
 %DIF DIFCODE_CTRADITIONAL
@@ -5697,7 +5697,7 @@ verbatim[*]?
 %DIF END DIFCODE_CFONT
 
 %DIF DIFCODE_FONTSTRIKE
-  moredelim=[il][\scriptsize \sout]{\%DIF\ <\ },
+  moredelim=[il][\scriptsize \strikeThrough]{\%DIF\ <\ },
   moredelim=[il][\sffamily]{\%DIF\ >\ }
 %DIF END DIFCODE_FONTSTRIKE
 
@@ -5717,8 +5717,8 @@ verbatim[*]?
 %DIF END DIFCODE_CCHANGEBAR
 
 %DIF DIFCODE_CULINECHBAR
-  moredelim=[il][\color{red}\sout]{\%DIF\ <\ },
-  moredelim=[il][\color{blue}\uwave]{\%DIF\ >\ }
+  moredelim=[il][\color{red}\strikeThrough]{\%DIF\ <\ },
+  moredelim=[il][\color{blue}\underLine]{\%DIF\ >\ }
 %DIF END DIFCODE_CULINECHBAR
 
 %DIF DIFCODE_CFONTCHBAR