Correct bookmark and TOC links

As links had the same number (E and 5), hyperref was always linking to
the first one. This meant that there was no quick way to access Unit 5,
because each link was connecting to Unit E instead. This fix added an
explicit method in hyperref to set the correct links.

Author: Kayzels

units/unit04.tex

@@ -135,6 +135,7 @@
 	\newcounter{oldchapter}
 	\setcounter{oldchapter}{\value{chapter}}
 	\setcounter{chapter}{4}
+	\renewcommand{\theHchapter}{E\Alph{chapter}}
 	\renewcommand{\thechapter}{\Alph{chapter}}
 	\chapter{Boolean Algebra and Logic Circuits}
 		\label{ch:boolean}
@@ -527,5 +528,6 @@
 
 	\setcounter{chapter}{\value{oldchapter}}
 	\renewcommand{\thechapter}{\arabic{chapter}}
+	\renewcommand{\theHchapter}{\arabic{chapter}}
 
 \end{document}