Introduce names for header and row color in the tables so that they are the same throughout the manual and can be changed easily

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@22501 a1c6a512-1295-4272-9138-f99709370657
diff --git a/manual/appendix/config_file_options.tex b/manual/appendix/config_file_options.tex
index 01f098ee..d7ee75c 100644
--- a/manual/appendix/config_file_options.tex
+++ b/manual/appendix/config_file_options.tex
@@ -6,7 +6,7 @@
 % for the html output.
 \ifpdfoutput{\newcommand{\localendhead}{\endhead}}%
     {\newcommand{\localendhead}{}}
-  \rowcolors{1}{}{gray!30}
+  \rowcolors{1}{}{tblrowbgcolor}
   \begin{longtable}{@{}>{\raggedright}p{.35\textwidth}@{}>{\raggedright}p{.4\textwidth}@{}p{.25\textwidth}@{}}
     \toprule
     \rowcolor{white} \textbf{Setting} & \textbf{Allowed Values} & \textbf{Unit}\\
diff --git a/manual/appendix/file_formats.tex b/manual/appendix/file_formats.tex
index 87eed69..e0f5161 100644
--- a/manual/appendix/file_formats.tex
+++ b/manual/appendix/file_formats.tex
@@ -3,7 +3,7 @@
 \section{\label{ref:Supportedfileformats}Supported file formats}
 \begin{table}
 \begin{center}
-\rowcolors{1}{}{gray!30}
+\rowcolors{1}{}{tblrowbgcolor}
 \begin{tabularx}{\textwidth}{clp{7em}X}\toprule
 \textbf{Icon} & \textbf{File Type} & \textbf{Extension} 
   & \textbf{Action when selected} \\\midrule%
@@ -83,7 +83,7 @@
   \section{\label{ref:Supportedaudioformats}Supported audio formats}
   \begin{table}
   \begin{center}
-  \rowcolors{1}{}{gray!30}
+  \rowcolors{1}{}{tblrowbgcolor}
   \begin{tabularx}{\textwidth}{lp{6em}X}\toprule
   \textbf{Format} & \textbf{Extension} & \textbf{Notes} \\\midrule
     \multicolumn{2}{c}{\textbf{Lossy codecs}}\\
diff --git a/manual/configure_rockbox/file_view.tex b/manual/configure_rockbox/file_view.tex
index e134934..3bf7c07 100644
--- a/manual/configure_rockbox/file_view.tex
+++ b/manual/configure_rockbox/file_view.tex
@@ -30,7 +30,7 @@
   be compared separately. The following table demonstrates the two sortings.
   \begin{table}
   \begin{center}  
-  \rowcolors{1}{}{gray!30}
+  \rowcolors{1}{}{tblrowbgcolor}
     \begin{tabularx}{.8\textwidth}{XX}
     \toprule
       \textbf{As whole numbers} & \textbf{As digits}\\
diff --git a/manual/configure_rockbox/sound_settings.tex b/manual/configure_rockbox/sound_settings.tex
index dcf543a..c3ce1f4 100644
--- a/manual/configure_rockbox/sound_settings.tex
+++ b/manual/configure_rockbox/sound_settings.tex
@@ -81,7 +81,7 @@
   %
   \begin{table}
   \begin{center}
-  \rowcolors{1}{}{gray!30}
+  \rowcolors{1}{}{tblrowbgcolor}
   \begin{tabularx}{\textwidth}{lX}\toprule
       \textbf{Setting} & \textbf{Description} \\\midrule
         Stereo
@@ -199,7 +199,7 @@
     %
     \begin{table}[h!]
       \begin{center}
-      \rowcolors{1}{}{gray!30}
+      \rowcolors{1}{}{tblrowbgcolor}
         \begin{tabular}{@{}lc@{}}\toprule
           Setting & Value \\\midrule
           MDB Strength & 50dB \\
diff --git a/manual/plugins/brickmania.tex b/manual/plugins/brickmania.tex
index 039134f..536c4a1 100644
--- a/manual/plugins/brickmania.tex
+++ b/manual/plugins/brickmania.tex
@@ -9,7 +9,7 @@
 \subsubsection{Special items}
 \begin{table}
     \begin{center}
-    \rowcolors{1}{}{gray!30}
+    \rowcolors{1}{}{tblrowbgcolor}
     \begin{tabularx}{.75\textwidth}{clX}\toprule
     \textbf{Displayed} & \textbf{Name} & \textbf{Description}\\\midrule
     N & Normal & Returns paddle to normal.\\
diff --git a/manual/plugins/goban.tex b/manual/plugins/goban.tex
index f4cf090..fe343b0 100644
--- a/manual/plugins/goban.tex
+++ b/manual/plugins/goban.tex
@@ -35,7 +35,7 @@
 
 \begin{table}
   \begin{center}
-  \rowcolors{1}{}{gray!30}
+  \rowcolors{1}{}{tblrowbgcolor}
     \begin{tabularx}{\textwidth}{lX}\toprule
       \textbf{Mark} & \textbf{Meaning} \\ \midrule
       \emph{+ } & There are nodes after the current node in the SGF tree. \\
diff --git a/manual/plugins/pacbox.tex b/manual/plugins/pacbox.tex
index 289ab95..96979b8 100644
--- a/manual/plugins/pacbox.tex
+++ b/manual/plugins/pacbox.tex
@@ -11,7 +11,7 @@
 ``Midway Pacman''.
 \begin{table}
 \begin{center}
-  \rowcolors{1}{}{gray!30}
+  \rowcolors{1}{}{tblrowbgcolor}
   \begin{tabular}{ll}\toprule
     \textbf{Filename} & \textbf{MD5 checksum}\\\midrule
     pacman.5e & 2791455babaf26e0b396c78d2b45f8f6\\
diff --git a/manual/preamble.tex b/manual/preamble.tex
index 2495f13..8bbce06 100644
--- a/manual/preamble.tex
+++ b/manual/preamble.tex
@@ -60,6 +60,10 @@
 
 \newcommand{\fixme}[1]{\textbf{\textcolor{red}{#1}}}
 
+% Colors used to typeset table headers and alternating table rows
+\colorlet{tblhdrbgcolor}{gray!60} % Background color for headers
+\colorlet{tblrowbgcolor}{gray!30} % Background color for rows
+
 \usepackage{fancyhdr}
 \usepackage{graphicx}
 \usepackage{verbatim}
@@ -210,7 +214,7 @@
 % Note: you still need to enclose this with \begin{table} / \end{table}
 % Cheers for the usenet helping me building this up :)
 \newenvironment{tagmap}[2]{%
-\rowcolors{1}{}{gray!30}
+\rowcolors{1}{}{tblrowbgcolor}
   \expandafter\let\expandafter\SavedEndTab\csname endtabular*\endcsname
   \expandafter\renewcommand\expandafter*\csname endtabular*\endcsname{%
     \bottomrule
@@ -320,7 +324,7 @@
 % Main Unit Key  &  Remote Key  &  Description \\
 
 \newenvironment{btnmap}[2]{%
-  \rowcolors{1}{}{gray!30}
+  \rowcolors{1}{}{tblrowbgcolor}
   \expandafter\let\expandafter\SavedEndTab\csname endtabular*\endcsname
   \expandafter\renewcommand\expandafter*\csname endtabular*\endcsname{%
     \bottomrule
diff --git a/manual/rockbox_interface/tagcache.tex b/manual/rockbox_interface/tagcache.tex
index e9d0c3e..09a7199 100644
--- a/manual/rockbox_interface/tagcache.tex
+++ b/manual/rockbox_interface/tagcache.tex
@@ -114,7 +114,7 @@
 
 \begin{table}
 \begin{center}
-\rowcolors{1}{}{gray!30}
+\rowcolors{1}{}{tblrowbgcolor}
   \begin{tabularx}{.75\textwidth}{XXX}%
   \toprule%
   \textbf{Tag}   & \textbf{Type}  & \textbf{Origin} \\