Merge branch 'feature/yaml-header-friendlyness' into 'master'

do not bark on yaml headers

See merge request !30

.markdownlint.json

 {
   "default": true,
   "MD013": { "line_length": 120 },
-  "MD024": { "siblings_only": true }
-}
\ No newline at end of file
+  "MD024": { "siblings_only": true },
+  "MD041": false
+}

chapters/yaml-header.md

 ---
 title: 'SUB RDD Technical Reference'
-...
\ No newline at end of file
+...
+

technical-reference-main.txt

+chapters/yaml-header.md
 chapters/about.md
 chapters/explanatory-notes.md
 chapters/style-guides.md