add frontmatter to files in the master branch and make consistent file and folder names
Merge branch 'master' into gh-pages

Conflicts:
	Hubs/hubs.md
	R/R.md
	R/R20-DataStructures.md
	Stats/stats00-preface.md
	Stats/stats21-linearRegression.md
	checklists/analysingData.md
	checklists/checklists.md
	checklists/whichAnalysis.md
changes to frontmatter
Merge branch 'master' into gh-pages

Conflicts:
	Hubs/hubs.md
	R/R.md
	Stats/stats00-preface.md
	checklists/checklists.md