控制台提示Could not find HammerJS. Certain Angular Material components may not work correctly.是怎么回事，是一个警告信息黄色的叹号，我只要使用md-slide-toggle就出现这个问题，我的cli是1.1.0的material是2.0.0-beta 0.7的

{
 "name": "scss2",
 "version": "0.0.0",
 "license": "MIT",
 "scripts": {
   "ng": "ng",
   "start": "ng serve",
   "build": "ng build",
   "test": "ng test",
   "lint": "ng lint",
   "e2e": "ng e2e"
 },
 "private": true,
 "dependencies": {
   "@angular/animations": "^4.4.3",
   "@angular/common": "^4.0.0",
   "@angular/compiler": "^4.0.0",
   "@angular/core": "^4.0.0",
   "@angular/forms": "^4.0.0",
   "@angular/http": "^4.0.0",
   "@angular/material": "^2.0.0-beta.7",
   "@angular/platform-browser": "^4.0.0",
   "@angular/platform-browser-dynamic": "^4.0.0",
   "@angular/router": "^4.0.0",
   "core-js": "^2.4.1",
   "rxjs": "^5.1.0",
   "zone.js": "^0.8.4"
 },
 "devDependencies": {
   "@angular/cli": "1.1.0",
   "@angular/compiler-cli": "^4.0.0",
   "@angular/language-service": "^4.0.0",
   "@types/jasmine": "2.5.45",
   "@types/node": "~6.0.60",
   "codelyzer": "~3.0.1",
   "jasmine-core": "~2.6.2",
   "jasmine-spec-reporter": "~4.1.0",
   "karma": "~1.7.0",
   "karma-chrome-launcher": "~2.1.1",
   "karma-cli": "~1.0.1",
   "karma-jasmine": "~1.1.0",
   "karma-jasmine-html-reporter": "^0.2.2",
   "karma-coverage-istanbul-reporter": "^1.2.1",
   "protractor": "~5.1.2",
   "ts-node": "~3.0.4",
   "tslint": "~5.3.2",
   "typescript": "~2.3.3"
 }
}