Issue #2487025 by shellshocked59, harings_rob, rteijeiro, subhojit777, vijaycs85, ashutoshsngh, aburrows, swetashahi, mradcliffe, Wim Leers, lauriii, LewisNyman, Bojhan, DeeLay, B_man, davidhernandez, lizzjoy, lweinmeister, wizonesolutions, arh1, GenerUmali, tstoeckler: Remove contextual links in Seven

Issue #1971860 by arh1, shanethehat, Fabianx: Document that Twig debug mode can cause automated tests to fail