Added environment to unify button mapping tables. Adjust plugins to use it.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@9475 a1c6a512-1295-4272-9138-f99709370657

manual/plugins/rockblox.tex

@@ -10,14 +10,11 @@ cleared, but if the blocks reach the top row then you lose.
 The controls for this game (with the Jukebox turned so that the buttons
 are to the right of the screen) are:
 
-\begin{table}[h!]
-\begin{center}
-\begin{tabular}{@{}ll@{}}\toprule
-\textbf{Key} & \textbf{Action} \\\midrule
+\begin{table}
+\begin{btnmap}{}{}
 UP & Rotate piece \\
 LEFT/RIGHT & Move piece to the left/right \\
 DOWN & Move faster the piece downwards \\
-OFF & Exit Rockblox\\\bottomrule
-\end{tabular}
-\end{center}
+OFF & Exit Rockblox\\
+\end{btnmap}
 \end{table}