{
  "name": "ethereum-webpack-example-dapp",
  "version": "1.0.0",
  "description": "Example Ethereum (Solidity) smart contract decentralized app with Webpack.",
  "main": "index.js",
  "scripts": {
    "start": "webpack --watch",
    "build": "webpack"
  },
  "repository": {
    "type": "git",
    "url": "https://github.com/uzyn/ethereum-webpack-example-dapp"
  },
  "keywords": [
    "webpack",
    "decentralized app",
    "decentralization",
    "ethereum",
    "solidity",
    "dapp",
    "template"
  ],
  "bugs": {
    "url": "https://github.com/uzyn/ethereum-webpack-example-dapp/issues"
  },
  "author": "U-Zyn Chua <chua@uzyn.com> (http://uzyn.com)",
  "license": "MIT",
  "devDependencies": {
    "babel-core": "^6.7.7",
    "babel-preset-es2015": "^6.6.0",
    "solc-loader": "^1.0.0-rc.3",
    "web3": "^0.15.3",
    "web3-loader": "^1.0.0-rc.2",
    "webpack": "^1.13.0"
  }
}

{
  "name": "ethereum-webpack-example-dapp",
  "version": "1.0.0",
  "description": "Example Ethereum (Solidity) smart contract decentralized app with Webpack.",
  "main": "index.js",
  "scripts": {
    "start": "webpack --watch",
    "build": "webpack"
  },
  "repository": {
    "type": "git",
    "url": "https://github.com/uzyn/ethereum-webpack-example-dapp"
  },
  "keywords": [
    "webpack",
    "decentralized app",
    "decentralization",
    "ethereum",
    "solidity",
    "dapp",
    "template"
  ],
  "bugs": {
    "url": "https://github.com/uzyn/ethereum-webpack-example-dapp/issues"
  },
  "author": "U-Zyn Chua <chua@uzyn.com> (http://uzyn.com)",
  "license": "MIT",
  "devDependencies": {
    "babel-core": "^6.7.7",
    "babel-loader": "^6.2.4",
    "babel-preset-es2015": "^6.6.0",
    "solc-loader": "^1.0.0-rc.3",
    "web3": "^0.15.3",
    "web3-loader": "^1.0.0-rc.2",
    "webpack": "^1.13.0"
  }
}

Include babel-loader as dev dependency
Include babel-loader as dev dependency

I could very well be wrong, but I think that babel-loader webpack plugin is required.