Move testrpc to top-level package.json and standardize some versions

packages/0x.js/package.json

@@ -61,7 +61,6 @@
     "copyfiles": "^1.2.0",
     "coveralls": "^3.0.0",
     "dirty-chai": "^2.0.1",
-    "ethereumjs-testrpc": "6.0.3",
     "json-loader": "^0.5.4",
     "mocha": "^4.0.0",
     "npm-run-all": "^4.0.2",
@@ -79,7 +78,7 @@
     "types-ethereumjs-util": "0xProject/types-ethereumjs-util",
     "typescript": "~2.6.1",
     "web3-provider-engine": "^13.0.1",
-    "web3-typescript-typings": "^0.7.1",
+    "web3-typescript-typings": "^0.7.2",
     "webpack": "^3.1.0"
   },
   "dependencies": {