Issue #3278493 by mglaman, rabbitlair, mherchel, Purencool, dww, benjifisher,...

Issue #3278493 by mglaman, rabbitlair, mherchel, Purencool, dww, benjifisher, lauriii, andy-blum, AdamPS, jwilson3, alexpott, smustgrave, rlahoda, akalata, ckrina, bnjmnm, crasx, mndonx, hbrokmeier, callinmullaney: Make it easier for theme builders to enable Twig debugging and disable render cache