Add facet headers to facet_grid
Merge branch 'master' (early part) into facet-headers
Merge branch 'master' (early part) into facet-headers
Merge branch 'master' (early part) into facet-headers

Conflicts:
	R/facet-grid-.r
Merge branch 'master' into facet-headers
Merge branch 'facet-headers' into develop
more ignores
Merge branch 'hygiene' into develop