title: Error TS2304 with tsc but not with Webpack, for names in project d.ts files
body: <h2>Problem</h2>
  <p>If I type <code>tsc main-test.ts --noEmit</code>, many <code>TS2304: Cannot find name TestInfo</code> error messages are displayed. The names it can't find are interfaces declared in <code>d.ts</code> files I have created in the project directory, eg <code>testGlobals.d.ts</code> below.</p>
  <p>If I compile with Webpack and awesome-typescript-loader (<code>node_modules\.bin\webpack --config wtest.webpack.config.js</code>), these messages do not appear - the project compiles successfully.</p>
  <p>Unfortunately, the same errors show up on Travis CI, even though the scripts that run on the CI server are compiled by webpack. How do I get rid of these errors?</p>
  <br>
  <h2>I have tried</h2>
  <p>Adding the project source directory to typeRoots in <code>tsconfig.json</code> in addition to <code>node_modules/@types</code>.</p>
  <br>
  <h2>Relevant files</h2>
  <p>wtest.webpack.config.js</p>
  <pre><code>var path = require('path');
  var webpack = require('webpack');
  
  
  var entryObj = {
      'test-script': path.join(__dirname, '/test/main-test.ts')
  };
  var manifestFile = '/test/manifest.json';
  var outdir = '/dist/test';
  var moduleRulesInclude = [path.join(__dirname, 'src'), path.join(__dirname, 'test')];
  var devtool = 'cheap-source-map';
  
  module.exports = {
      devtool: devtool,
      entry: entryObj,
      resolve: {
          extensions: ['.js', '.ts', '.tsx']
      },
      module: {
          rules: [{
              test: /\.tsx?$/,
              loaders: ['awesome-typescript-loader'],
              include: moduleRulesInclude
          }]
      },
      // Workaround for `can't resolve module 'fs'` issue
      node: {
          fs: 'empty',
          module: false
      }
  };
  </code></pre>
  <p>tsconfig.json</p>
  <pre><code>{
    &quot;compilerOptions&quot;: {
      &quot;target&quot;: &quot;es6&quot;,
      &quot;module&quot;: &quot;commonjs&quot;,
      &quot;declaration&quot;: false,
      &quot;noImplicitAny&quot;: false,
      &quot;removeComments&quot;: true,
      &quot;experimentalDecorators&quot;: true,
      &quot;noLib&quot;: false,
      &quot;jsx&quot;: &quot;react&quot;,
      &quot;outDir&quot;: &quot;dist&quot;
    },
    &quot;exclude&quot;: [
      &quot;node_modules&quot;,
      &quot;static&quot;
    ]
  }
  </code></pre>
  <p>testGlobals.d.ts</p>
  <pre><code>interface TestInfo {
      testName: string;
      url: string;
      title: string;
      author: string;
      chapterUrls: string[];
      parser: ParserReturner;
  }
  </code></pre>