• Set#isDisjointWith renamed to Set#isDisjointFrom per tc39/proposal-set-methods#46.
• Set#isSubsetOf updated per tc39/proposal-set-methods#41, tc39/proposal-set-methods#45, tc39/proposal-set-methods#48.
• esnext.string.trim-{ left -> start, right -> end } renamed by names of main methods of the proposal.
• Fixed Array#forEach implementation, which in some cases was defined in sloppy mode.
• Fixed Reflect.metadata by the current behaviour of the spec.
• Fixed arity of Reflect.defineMetadata.
• Added conversion to boolean to result of deleteAll.
• Added a fallback for Weex JS engine, #461.
• Finally fixed #475.
• Many other minor internal fixes and improvements.