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/makefile

@@ -2,6 +2,8 @@
 LATEX := latexmk -cd -pdf -pdflatex="pdflatex -interaction=nonstopmode" -use-make
 EBOOK := tex4ebook -c tex4ebook.cfg
 CLEAN := latexmk -cd -c -use-make
+CHECK_1 := lacheck
+CHECK_2 := chktex 
 
 # List all files that are dependencies
 SRC_FIGURES := $(wildcard figures/fig-*.tex)
@@ -74,10 +76,14 @@ help:
 	@echo ""
 	@echo "default: builds the book in pdf format (serif)"
 	@echo ""
-	@echo "all: pdf and ebooks serif and sans-serif accessible version, same as build release"
+	@echo "all: pdf and ebooks serif and sans-serif accessible version, same as"
+	@echo "     build release"
 	@echo "bake: same as build all"
 	@echo "release_default: same as build all"
 	@echo ""
+	@echo "check: runs static analysis checker on LaTeX source to spot"
+	@echo "       programming or typographic mistakes"
+	@echo ""
 	@echo "clean: delete all intermediate files keep targets (pdf/ebook)"
 	@echo "mrproper: delete all generated files intermediate and pdf/ebooks"
 	@echo "clean_figures: delete intermediate TikZ files"
@@ -120,6 +126,16 @@ export_figures:
 figures: $(SRC_FIGURES)
 	$(LATEX) $<
 
+.PHONY: check
+# Goal is not really to have 0 warning reported but we should check we don't
+# add many and if we do, we know they are false positive
+check: $(SRC_TEX)
+	@echo "Running: " $(CHECK_1) 
+	$(CHECK_1) book.tex
+	@echo ""
+	@echo "Running: " $(CHECK_2) 
+	$(CHECK_2) book.tex
+
 .PHONY: clean_figures
 clean_figures:
 	$(CLEAN) $(SRC_FIGURES)