Improve typography (#120)

* Add unbreakable space before a reference or a citation

avoids ref to be put on next line or page...

* Add unbreakable space between I and verb

* Remove spacing before footnotes

Also moved it before the final sentence dots in many cases... might need
a review of what is best.  But this is a safe default choice from an
esthetic point of view.

* Improve footnotes and punctuations

Reverse order/kerning especially with sans-serif version.

* Remove manual enumerate

* Fix wording in a citation.

Reads better that way and is shorter.

* Use emph instead of italics

1) Markup semantic not style
2) Will deal with various level of empahasis
3) Was a mix of \it and \textit

* Fix usage of quotes

Also replaced some of then by \emph as it is (IMHO) more visually
pleasant.

* Captitalize before reference

* Correct dashes length

see here:
https://www.merriam-webster.com/words-at-play/em-dash-en-dash-how-to-use

* Remove space before label and homogenize caption

Apparently it can create a wrong reference, if notthing else shuts
texcheck up and cost nothing... so let's do it.

While at it adding a dot at the end of each caption.

* Add missing empty line before signature in preface

* Add a static checker target to makefile

Shall help prevent adding mistakes in new versions

book/figures/fig-baking-process.tex

@@ -11,7 +11,7 @@
   \node [block, below of=inverted_tray_method, node distance=3cm] (bake_30) {\footnotesize Bake dough for 30 minutes with steam};
   \node [block, right of=bake_30, node distance=3cm] (remove_steam) {\footnotesize Remove source of steam};
   \node [block, right of=remove_steam, node distance=3cm] (build_crust) {\footnotesize Build the crust};
-  \node [block, right of=build_crust, node distance=3cm] (finish_baking) {\footnotesize Stop baking 10-30 minutes later depending on crust preference};
+  \node [block, right of=build_crust, node distance=3cm] (finish_baking) {\footnotesize Stop baking 10--30 minutes later depending on crust preference};
   \path [line] (heat_oven) -- (score_dough);
   \path [line] (score_dough) -- (decide_steam);
   \path [line] (decide_steam) -- (inverted_tray_method);

book/figures/fig-liquid-starter-conversion.tex

@@ -18,6 +18,6 @@
   \path [line] (test) -- (ready_signs);
   \path [line] (ready_signs) -- node{\footnotesize no} (feed_again);
   \path [line] (ready_signs) -- node{\footnotesize yes} (last_feed);
-  \path [line] (last_feed) -- node{\footnotesize after 6-12 hours} (bread_dough);
+  \path [line] (last_feed) -- node{\footnotesize after 6--12 hours} (bread_dough);
 \end{tikzpicture}
 \end{document}

book/figures/fig-starter-maintenance.tex

@@ -14,12 +14,12 @@
   \path [line] (use_starter) -- (feed_starter);
   \node [decision, right of=feed_starter, node distance=3cm] (bake_next_day_check) {\footnotesize Bake next day?};
   \path [line] (feed_starter) -- (bake_next_day_check);
-  \node [block, right of=bake_next_day_check, node distance=3.5cm] (make_bread_dough) {\footnotesize Make bread dough again after 8-12 hours};
+  \node [block, right of=bake_next_day_check, node distance=3.5cm] (make_bread_dough) {\footnotesize Make bread dough again after 8--12 hours};
   \path [line] (bake_next_day_check) -- node{yes} (make_bread_dough);
   \node [decision, right of=use_starter, node distance=3cm] (bake_next_week_check) {\footnotesize Baking in next 2 weeks?};
   \node [block, right of=bake_next_week_check, node distance=3.5cm] (store_fridge) {\footnotesize Store starter in fridge at 4°C(40°F)};
   \path [line] (bake_next_week_check) -- node{yes} (store_fridge);
-  \node [block, right of=store_fridge, node distance=3cm] (feed_after_fridge) {\footnotesize Feed again using 1:5:5 ratio 8-12 hours before making dough};
+  \node [block, right of=store_fridge, node distance=3cm] (feed_after_fridge) {\footnotesize Feed again using 1:5:5 ratio 8--12 hours before making dough};
   \path [line] (store_fridge) -- (feed_after_fridge);
   \path [line] (bake_next_day_check) -- node{no} (bake_next_week_check);
   \node [decision, below of=use_starter, node distance=3cm] (freezer_check) {\footnotesize Have a freezer?};

book/figures/fig-stiff-starter-conversion.tex

@@ -19,7 +19,7 @@
   \path [line] (repeated_3_times) -- node{\footnotesize no} (feed_again);
   \path [line] (ready_signs) -- node{\footnotesize no} (feed_again);
   \path [line] (ready_signs) -- node{\footnotesize yes} (last_feed);
-  \path [line] (last_feed) -- node{\footnotesize after 6-12 hours} (bread_dough);
+  \path [line] (last_feed) -- node{\footnotesize after 6--12 hours} (bread_dough);
   \path [line] (feed_new_ratio) -- (too_dry);
   \path [line] (add_water) -- (next_day);
   \path [line] (too_dry) -- node{\footnotesize no} (next_day);

book/figures/fig-wheat-sourdough-starter-process.tex

@@ -4,9 +4,9 @@
 \begin{tikzpicture}[node distance = 3cm, auto]
   \node [decision] (init) {\footnotesize Starter last fed within 3 days?};
   \node [block, right of=init, node distance=4cm] (feed_no_branch)
-    {\footnotesize Feed starter twice. 48 hours before and 6-12 hours before};
+    {\footnotesize Feed starter twice. 48 hours before and 6--12 hours before};
   \node [block, below of=feed_no_branch, node distance=3cm] (feed_yes_branch)
-    {\footnotesize Feed starter once 6-12 hours before making dough};
+    {\footnotesize Feed starter once 6--12 hours before making dough};
   \node [block, right of=feed_no_branch, node distance=6cm] (high_ratio)
     {\footnotesize Use a 1:10:10 ratio. 10g starter, 100g flour, 100g water};
   \node [block, right of=feed_yes_branch, node distance=3cm] (low_ratio)