Issue #474684 by bnjmnm, dawehner, tedbow, pfrenssen, JohnAlbin, ademarco,...

Issue #474684 by bnjmnm, dawehner, tedbow, pfrenssen, JohnAlbin, ademarco, kalpaitch, vdacosta@voidtek.com, rensingh99, markcarver, jungle, jhedstrom, RobLoach, almaudoh, kevineinarsson, shaal, dpagini, thedavidmeister, sreynen, Snugug, Miguel.kode, kamkejj, alexpott, Pol, sun, Wim Leers, lauriii, tim.plunkett, eaton: Allow themes to declare dependencies on modules