Removing unused dependencies

PhantomJS is not used in axios.

package.json

@@ -53,7 +53,6 @@
     "karma-jasmine": "^1.0.2",
     "karma-jasmine-ajax": "^0.1.13",
     "karma-opera-launcher": "^1.0.0",
-    "karma-phantomjs-launcher": "^1.0.0",
     "karma-safari-launcher": "^1.0.0",
     "karma-sauce-launcher": "^1.1.0",
     "karma-sinon": "^1.0.5",
@@ -61,7 +60,6 @@
     "karma-webpack": "^1.7.0",
     "load-grunt-tasks": "^3.5.2",
     "minimist": "^1.2.0",
-    "phantomjs-prebuilt": "^2.1.7",
     "sinon": "^1.17.4",
     "webpack": "^1.13.1",
     "webpack-dev-server": "^1.14.1",