Upgrade version of Truffle to 3.4.6

package.json

@@ -35,6 +35,7 @@
     "babel-preset-stage-2": "^6.18.0",
     "babel-preset-stage-3": "^6.17.0",
     "babel-register": "^6.23.0",
+    "babel-polyfill": "^6.23.0",
     "chai": "^4.0.2",
     "chai-as-promised": "^7.0.0",
     "chai-bignumber": "^2.0.0",
@@ -43,6 +44,6 @@
     "mocha-lcov-reporter": "^1.3.0",
     "moment": "^2.18.1",
     "solidity-coverage": "^0.1.7",
-    "truffle": "3.2.2"
+    "truffle": "^3.4.6"
   }
 }