Merge remote-tracking branch 'refs/remotes/github.com/master' into layoutdir

Conflicts:
	test/actual/multi/dest1/helpers.html
	test/actual/multi/dest1/helpers.md
	test/actual/multi/dest2/sub-dest/helpers.html
	test/actual/paths/helpers.html
	test/actual/yaml/document.html
	test/actual/yaml/lists.html
revert project description
reorganize some test files
add info about `data` files