Don't allow further binary operators after an arrow expression
Don't allow further binary operators after an arrow expression

Issue #475

TimothyGu/acorn,MarcelGerber/acorn,marijnh/acorn,mysticatea/acorn,mathiasbynens/acorn,mathiasbynens/acorn,MarcelGerber/acorn,marijnh/acorn,ajaxorg/acorn,ternjs/acorn,ajaxorg/acorn,mysticatea/acorn,ajaxorg/acorn,mysticatea/acorn,TimothyGu/acorn,ternjs/acorn,TimothyGu/acorn,marijnh/acorn,mathiasbynens/acorn,ternjs/acorn,MarcelGerber/acorn