title: Invalid configuration object. Webpack has been initialised using a configuration
body: <p>As of this morning, with Angular CLI <code>1.0.0-beta.14</code> I <code>ng new try3</code> and <code>ng serve</code> and get the following error:</p>
  
  <pre><code>Invalid configuration object. Webpack has been initialised using a configuration object that does not match the API schema.
   - configuration has an unknown property 'tslint'. These properties are valid:
     object { amd?, bail?, cache?, context?, devServer?, devtool?, entry, externals?, loader?, module?, name?, dependencies?, node?, output?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, stats?, target?, watch?, watchOptions? }
   - configuration.module has an unknown property 'preLoaders'. These properties are valid:
     object { rules?, loaders?, noParse?, unknownContextRequest?, unknownContextRegExp?, unknownContextRecursive?, unknownContextCritical?, exprContextRequest?, exprContextRegExp?, exprContextRecursive?, exprContextCritical?, wrappedContextRegExp?, wrappedContextRecursive?, wrappedContextCritical? }
     Options affecting the normal modules (`NormalModuleFactory`).
   - configuration.node.global should be a boolean.
   - configuration.resolve has an unknown property 'root'. These properties are valid:
     object { modules?, descriptionFiles?, plugins?, mainFields?, aliasFields?, mainFiles?, extensions?, enforceExtension?, moduleExtensions?, enforceModuleExtension?, alias?, symlinks?, unsafeCache?, cachePredicate?, fileSystem?, resolver? }
   - configuration.resolve.extensions[0] should not be empty.
  WebpackOptionsValidationError: Invalid configuration object. Webpack has been initialised using a configuration object that does not match the API schema.
   - configuration has an unknown property 'tslint'. These properties are valid:
     object { amd?, bail?, cache?, context?, devServer?, devtool?, entry, externals?, loader?, module?, name?, dependencies?, node?, output?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, stats?, target?, watch?, watchOptions? }
   - configuration.module has an unknown property 'preLoaders'. These properties are valid:
     object { rules?, loaders?, noParse?, unknownContextRequest?, unknownContextRegExp?, unknownContextRecursive?, unknownContextCritical?, exprContextRequest?, exprContextRegExp?, exprContextRecursive?, exprContextCritical?, wrappedContextRegExp?, wrappedContextRecursive?, wrappedContextCritical? }
     Options affecting the normal modules (`NormalModuleFactory`).
   - configuration.node.global should be a boolean.
   - configuration.resolve has an unknown property 'root'. These properties are valid:
     object { modules?, descriptionFiles?, plugins?, mainFields?, aliasFields?, mainFiles?, extensions?, enforceExtension?, moduleExtensions?, enforceModuleExtension?, alias?, symlinks?, unsafeCache?, cachePredicate?, fileSystem?, resolver? }
   - configuration.resolve.extensions[0] should not be empty.
      at webpack (/home/jan/src/fm-repos/try3/node_modules/webpack/lib/webpack.js:16:9)
      at Class.run (/home/jan/src/fm-repos/try3/node_modules/angular-cli/tasks/serve-webpack.js:23:27)
      at /home/jan/src/fm-repos/try3/node_modules/angular-cli/commands/serve.js:84:26
      at process._tickCallback (internal/process/next_tick.js:103:7)
  </code></pre>
  
  <p>The last time I <code>ng new</code> a project was a few days ago -- at that point it worked file. Here's my environment:</p>
  
  <pre><code>angular-cli: 1.0.0-beta.14
  node: 6.5.0
  os: linux x64
  </code></pre>