new grunt task for setting phantomjs binary

tasks/options/phantomjs.js

+module.exports = function(config,grunt) {
+  'use strict';
+  grunt.registerTask('phantomjs', 'Copy phantomjs binary from node', function() {
+    var m=grunt.file.read("./node_modules/karma-phantomjs-launcher/node_modules/phantomjs/lib/location.js")
+    var p=/= \"([^\"]*)\"/.exec(m);
+    if (grunt.file.exists(p[1])) {
+      grunt.log.writeln('Using '+ p[1]);
+      grunt.file.copy(p[1],'vendor/phantomjs/phantomjs');
+    }
+  });
+};
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