Issue #2594937 by Peacog, cilefen, Sagar Ramgade, chgasparoto, aerozeppelin, iStryker, feraline, alvar0hurtad0, Cottser, Wim Leers, xjm, sebas5384, almaudoh, gvso, racarvalho1987: Empty 'libraries:' in theme .info.yml file produces confusing PHP warning

Issue #2003266 by kenianbei, misselbeck, iStryker, Dan Reinders: Rename Views method show_build_group_button() to showBuildGroupButton().