merged for revert
Merge branch 'devel' of https://github.com/triAGENS/ArangoDB into devel
Revert "tabs replaced with spaces"

This reverts commit f38493e4c678b06dcb09b3f1fc918ba6bb8c367e.

Conflicts:
	Documentation/Books/Makefile
	Documentation/Books/Users/SUMMARY.md
	Documentation/Books/Users/localtheme/templates/includes/book/header.html