Remove centering for floats (#364)

This was a bad idea...:
https://tex.stackexchange.com/questions/2651/should-i-use-center-or-centering-for-figures-and-tables

floatrows not sure how it should work with flowcharts... so we use
centring

I don't want to redefine all floats either as we use them for chapters
title page.

book/sourdough-starter/sourdough-starter-types.tex

@@ -27,14 +27,13 @@ starter has half as much water as flour, as summarized in
 Table~\ref{tab:starter-types-comparison}.
 
 \begin{table}[htp!]
-    \begin{center}
+    \centering
         \input{tables/table-starter-types.tex}
         \caption[Different types of sourdough]{A comparison of different
             sourdough starter types and their respective properties. The only
             difference is the amount of water (hydration) that is used when
             feeding the starter.}%
         \label{tab:starter-types-comparison}
-    \end{center}
 \end{table}
 
 You can change your starter type by just adjusting the feeding ratio of how
@@ -123,19 +122,18 @@ starter's flavor by changing the type to a liquid starter.
 \label{section:liquid-starter}
 
 \begin{figure}[!htb]
-\begin{center}
+\centering
   \includegraphics[width=0.5\textwidth]{sourdough-starter-liquid.jpg}
   \caption[Liquid starter]{A liquid sourdough starter features a high level of
       water. The high water amount boosts lactic acid producing bacteria.
       After a while the liquid and flour start to separate. Bubbles on the
       side of the flour indicate that the starter is ready to be used.}%
   \label{fig:liquid-sourdough-starter}
-\end{center}
 \end{figure}
 
 
 \begin{flowchart}[!htb]
-\begin{center}
+\centering
   \input{figures/fig-liquid-starter-conversion.tex}
   \caption[Converting to a liquid starter]{The process to convert your regular
       or stiff starter into a liquid starter. The whole process takes around 
@@ -149,7 +147,6 @@ starter's flavor by changing the type to a liquid starter.
       starter your created stiff starter will feature both dairy
       and vinegary notes.}%
   \label{flc:liquid-starter-conversion}
-\end{center}
 \end{flowchart}
 
 The liquid starter is made at a hydration of around \qty{500}{\percent}. This means
@@ -242,7 +239,7 @@ for a visual example of the starter's required hydration level.
 \end{figure}
 
 \begin{flowchart}[!htb]
-\begin{center}
+\centering
   \input{figures/fig-stiff-starter-conversion.tex}
   \caption[Converting to a stiff starter]{The process to convert your regular
       starter into a stiff starter. The whole process takes around 3 days. The
@@ -252,7 +249,6 @@ for a visual example of the starter's required hydration level.
       \qty{50}{\percent} hydration level for the starter. If the dough is too
       stiff consider increasing this to \qty{60}{\percent}.}%
   \label{fig:stiff-starter-conversion}
-\end{center}
 \end{flowchart}
 
 In the stiffer environment the yeast thrives more. This means you will have

book/sourdough-starter/sourdough-starter.tex

@@ -38,11 +38,10 @@ comes in handy. Let's look at the default recipe with baker's
 math and then adjust it for the \qty{1.4}{\kg} flour quantity.
 
 \begin{table}[!htb]
-\begin{center}
+\centering
   \input{tables/table-bakers-math-example.tex}
   \caption[Baker's math example]{An example table demonstrating how to
       properly calculate using baker's math}
-\end{center}
 \end{table}
 
 Note how each of the ingredients is calculated as a percentage
@@ -55,12 +54,11 @@ more flour available the next day. As mentioned the next day
 we have \qty{1.4}{\kg} at hand (\qty{1400}{\gram}).
 
 \begin{table}[!htb]
-    \begin{center}
+    \centering
         \input{tables/table-recipe-bakers-math.tex}
         \caption[Another baker's math example]{An example recipe that uses
             \qty{1400}{\gram} as its baseline and is then calculated using
             baker's math.}
-    \end{center}
 \end{table}
 
 For each ingredient we calculate the percentage
@@ -133,12 +131,11 @@ I~like to use a glass and place another
 inverted one on top.
 
 \begin{flowchart}[!htb]
-\begin{center}
+\centering
   \input{figures/fig-starter-process.tex}
   \caption[The full sourdough starter process]{The process of making a sourdough
       starter from scratch.}%
   \label{fig:sourdough-starter-process}
-\end{center}
 \end{flowchart}
 
 Now an epic battle begins. In one study~\cite{yeasts+biocontrol+agent}
@@ -272,14 +269,13 @@ yeast has been isolated like this from century old sourdough
 starters.
 
 \begin{flowchart}[!htb]
-\begin{center}
+\centering
   \input{figures/fig-starter-readiness.tex}
   \caption[Determining sourdough starter readiness]{A flow chart showing you how to
       determine if your sourdough starter is ready to be used.  For checking
       readiness look at a size increase and take note of your starter's smell.
       Both are important indicators to check for readiness.}%
   \label{fig:sourdough-starter-readiness}
-\end{center}
 \end{flowchart}
 
 The key sign to look at is bubbles that you see in your starter
@@ -346,7 +342,7 @@ yeast part of your sourdough and balance the fermentation.
 \section{Maintenance}
 
 \begin{flowchart}[!htb]
-\begin{center}
+\centering
   \input{figures/fig-starter-maintenance.tex}
   \caption[Sourdough starter maintenance flowchart]{A full flowchart showing
       you how to conduct proper sourdough starter maintenance. You can use a
@@ -356,7 +352,6 @@ yeast part of your sourdough and balance the fermentation.
       \qty{100}{\percent} hydration level. Adjust the water content
       accordingly when you use a stiff starter.}%
   \label{fig:sourdough-maintenance-process}
-\end{center}
 \end{flowchart}
 
 You have made your sourdough starter and your first bread. How do you perform