Add a flowchart environnement and its listof

So we can more easily access those flowcharts from pdf and website,
rather than looking in the crowded list of figures.

book/wheat-sourdough/wheat-sourdough.tex

@@ -44,13 +44,13 @@ that tastes much better than any store-bought bread.
 
 \section{The process}
 
-\begin{figure}[!htb]
+\begin{flowchart}[!htb]
 \begin{center}
   \input{figures/fig-wheat-sourdough-process.tex}
   \caption{The typical process of making a wheat-based sourdough bread.}%
   \label{fig:wheat-sourdough-process}
 \end{center}
-\end{figure}
+\end{flowchart}
 
 The whole process of making great sourdough bread starts with
 readying your sourdough starter. The key to mastering
@@ -98,7 +98,7 @@ properties are passed on to your main dough. If your starter
 doesn't have a good balance of yeast to bacteria, so will your
 main dough.
 
-\begin{figure}[!htb]
+\begin{flowchart}[!htb]
 \begin{center}
   \input{figures/fig-wheat-sourdough-starter-process.tex}
   \caption[Process to prepare your starter before baking]{The process to check
@@ -111,7 +111,7 @@ main dough.
       water, use \qtyrange{50}{60}{\gram} of water for your stiff starter.}%
   \label{fig:process-starter-wheat-sourdough}
 \end{center}
-\end{figure}
+\end{flowchart}
 
 Generally, think of the dough you are mixing as a big starter with salt.
 After mixing all the ingredients, you have a green field environment again.
@@ -557,13 +557,13 @@ becomes more elastic and holds together better. This is the basis for trapping
 all the gases during the fermentation process. Without the gluten network,
 the gases would just diffuse out of your dough.
 
-\begin{figure}[!htb]
+\begin{flowchart}[!htb]
 \begin{center}
   \input{figures/fig-kneading-process.tex}
   \caption{The gluten development process for a wheat-based dough.}%
   \label{fig:wheat-sourdough-kneading-process}
 \end{center}
-\end{figure}
+\end{flowchart}
 
 It might sound odd, but the most important part of kneading is waiting. By
 waiting you are allowing your flour to soak up water. This way the gluten
@@ -769,7 +769,7 @@ predictable. The room for error (as shown in figure~\ref{fig:wheat-yeast-sourdou
 is much larger. The doughs are perfect to be made in a
 machine.
 
-\begin{figure}[!htb]
+\begin{flowchart}[!htb]
 \begin{center}
   \input{figures/fig-bulk-fermentation.tex}
   \caption[Process to check the bulk fermentation]{During the bulk
@@ -779,7 +779,7 @@ machine.
       options to check on the bulk fermentation progress.}%
   \label{fig:bulk-fermentation}
 \end{center}
-\end{figure}
+\end{flowchart}
 
 Experienced bakers will tell you to go by the look and feel of
 the dough. While this works if you have made hundreds of loaves,
@@ -1111,14 +1111,14 @@ once your sourdough finishes with the bulk fermentation stage.
 The step is required if you are making multiple loaves in one
 batch. It is optional if you are making a single loaf.
 
-\begin{figure}[!htb]
+\begin{flowchart}[!htb]
 \begin{center}
   \input{figures/fig-dividing-preshaping.tex}
   \caption[Dividing decision tree]{Dividing is only required when you are
       making multiple loaves in a single dough batch.}%
   \label{fig:dividing-decision-tree}
 \end{center}
-\end{figure}
+\end{flowchart}
 
 The goal of dividing your dough into smaller pieces is to portion
 your dough accordingly. This way you'll have multiple pieces of bread
@@ -1226,14 +1226,14 @@ your environment.
 
 \section{Shaping}
 
-\begin{figure}[!htb]
+\begin{flowchart}[!htb]
 \begin{center}
   \input{figures/fig-shaping-process.tex}
   \caption[Shaping process]{A schematic visualization of the shaping process
       including checks for an overfermented dough.}%
   \label{fig:shaping-decision-tree}
 \end{center}
-\end{figure}
+\end{flowchart}
 
 Shaping will give your dough the final shape before baking. After
 completing shaping, your dough proceeds to the proofing stage and
@@ -1451,7 +1451,7 @@ at a slower rate at colder temperatures. But I~doubt that they alter
 their biochemical processes. More research is needed on the topic
 of retarding and flavor development.
 
-\begin{figure}[!htb]
+\begin{flowchart}[!htb]
 \begin{center}
   \input{figures/fig-proofing-process.tex}
   \caption[Proofing process]{A schematic overview of the different steps of
@@ -1459,7 +1459,7 @@ of retarding and flavor development.
       on your availability and schedule.}%
   \label{fig:proofing-process}
 \end{center}
-\end{figure}
+\end{flowchart}
 
 To me, the sole purpose of cold proofing is its ability to allow you
 to better manage the timing of the whole process. Assuming you finished shaping