Fix html-minifier dependency.
Fix html-minifier dependency.

Current release cannot be used because html-minifier is listed as a devDependency (which doesn't get installed in real-world use).
ericclemmons/grunt-angular-templates,MillerRen/grunt-angular-templates,ericclemmons/grunt-angular-templates,sahat/grunt-angular-templates,MillerRen/grunt-angular-templates