Center TikZ figures

Because it looks better

book/baking/baking.tex

@@ -3,10 +3,12 @@ your dough into the oven. This is typically done after your
 dough has gone through the bulk fermentation and proofing stage.
 
 \begin{figure}[!htb]
+\begin{center}
   \input{figures/fig-baking-process.tex}
   \caption{A schematic visualization of the baking process using different
   sources of steam in a home oven.}%
   \label{fig:baking-process}
+\end{center}
 \end{figure}
 
 Some other breads like flatbreads
@@ -214,10 +216,12 @@ created from the dough and water source stays
 around your dough.
 
 \begin{figure}[!htb]
+\begin{center}
   \input{figures/fig-inverted-tray-method.tex}
   \caption{A schematic visualization the inverted tray baking method that
   works great for home ovens.}%
   \label{fig:inverted-tray-process}
+\end{center}
 \end{figure}