added support for TemplateElement in walker
added support for TemplateElement in walker

ternjs/acorn,marijnh/acorn,marijnh/acorn,mysticatea/acorn,TimothyGu/acorn,ternjs/acorn,marijnh/acorn,TimothyGu/acorn,ternjs/acorn,TimothyGu/acorn,mysticatea/acorn,mysticatea/acorn