Try fixing CI build

.eslintrc

@@ -11,6 +11,8 @@
     "no-use-before-define": 0,
     "wrap-iife": 0,
     "eqeqeq": 0,
-    "no-proto": 0
+    "no-proto": 0,
+    "no-cond-assign": 0,
+    "func-names": 0
   }
 }

package.json

@@ -26,14 +26,15 @@
   "dependencies": {},
   "devDependencies": {
     "babel-cli": "^6.10.1",
-    "babel-preset-es2015": "^6.16.0",
+    "babel-preset-env": "^1.6.0",
     "benchmark": "^2.1.1",
     "check-compose": "^3.2.0",
     "dependency-check": "^2.5.0",
     "eslint": "^3.7.0",
     "eslint-config-airbnb-base": "^11.0.0",
     "eslint-config-es5": "^0.5.0",
     "eslint-plugin-import": "^2.0.1",
+    "gzip-size-cli": "^2.1.0",
     "istanbul": "^1.1.0-alpha.1",
     "lodash": "^4.16.1",
     "nsp": "^2.1.0",
@@ -45,15 +46,16 @@
     "rollup-plugin-filesize": "^1.0.0",
     "rollup-plugin-uglify": "^1.0.0",
     "tape": "^4.2.2",
+    "uglify-js": "^2.8.29",
     "watch": "^1.0.1"
   },
   "scripts": {
     "cov": "npm run cov:clean && npm run cov:generate",
     "cov:clean": "rimraf ./coverage/",
-    "cov:generate": "babel-node --presets=es2015 ./node_modules/.bin/istanbul cover test",
+    "cov:generate": "babel-node --presets=env ./node_modules/.bin/istanbul cover test",
     "prepublish": "npm run check",
     "pretest": "npm run build",
-    "test": "babel-node --presets=es2015 test && npm run lint",
+    "test": "babel-node --presets=env test && npm run lint",
     "posttest": "node test/benchmark",
     "clean": "rimraf dist/*",
     "lint": "eslint src && eslint test",
@@ -67,7 +69,7 @@
     "check": "npm run audit && npm run deps",
     "watch": "watch 'clear && npm -s test' test/ src/",
     "minify": "uglifyjs src/stampit.js -c collapse_vars,evaluate=false,screw_ie8,unsafe,loops=false,keep_fargs=false,pure_getters,unused,dead_code,keep_fnames=[\"'stampit','Stamp'\"] -m --reserved stampit,Stamp -o dist/stampit.min.js --source-map dist/stampit.min.js.map",
-    "postminify": "ls -l dist/ && gzip-size --raw dist/stampit.min.js"
+    "postminify": "ls -l dist/ && echo GZIP size: && gzip-size --raw dist/stampit.min.js"
   },
   "license": "MIT",
   "npmName": "stampit",