title: Grunt generates empty file from typescript source
body: <p>I am using grunt to compile typescripts and generate some .js files from these. Problem is, for some reason I always get empty file in which is only one line - reference from compiled file. But is should contain quite complex javascript module.</p>
  
  <p>Gruntfile.js:</p>
  
  <pre><code>module.exports = function (grunt) {
      grunt.initConfig({
  
          pkg: grunt.file.readJSON("package.json"),
  
          clean: {
              dist: { src: ["dist"], force: true }
          },
  
          copy: {
  
          },
  
          typescript: {
              base: {
                  src: [
                      "AwesomeGrid/**/*.ts"
                  ],
                  //dest: "dist/grid-fp.js",
                  dest: "dist",
                  options: {
                      target: "es5"
                  }
              }
          }
      });
  
      grunt.loadNpmTasks("grunt-contrib-clean");
      grunt.loadNpmTasks("grunt-typescript");
  
      grunt.registerTask("default", ["clean", "typescript:base"]);
  };
  </code></pre>
  
  <p>package.json:</p>
  
  <pre><code>{
    "name": "FalsePositiveManagement",
    "version": "2.0.0-alpha",
    "private": true,
    "author": "Moravia s.r.o.",
    "license": "none",
    "devDependencies": {
      "grunt": "~0.4.5",
      "grunt-contrib-clean": "~0.6.0",
      "grunt-contrib-watch": "~0.6.1",
      "grunt-typescript": "^0.8.0"
    }
  }
  </code></pre>
  
  <p>source .ts file:</p>
  
  <pre><code>    ///&lt;reference path="../../typings/tsd.d.ts"/&gt;
  
      module Fp {
          export interface IGroupSettings {
              key: string;
              title: string;
              icon: string;
              url: string;
              active: boolean;
          }
  
          export interface IFPGridTableSettings {
              tableElement: JQuery;
              gridOptions: AwesomeGrid.IGridOptions;
          }
  </code></pre>
  
  <p>generated .js file:</p>
  
  <pre><code>///&lt;reference path="../../typings/tsd.d.ts"/&gt;
  </code></pre>
  
  <p>tsd.d.ts file:</p>
  
  <pre><code>    /// &lt;reference path="jquery/jquery.d.ts" /&gt;
  
      /// &lt;reference path="bootstrap/bootstrap.d.ts" /&gt;
  
      /// &lt;reference path="chance/chance.d.ts" /&gt;
  
      /// &lt;reference path="moment/moment.d.ts" /&gt;
  
      /// &lt;reference path="grid/grid.d.ts" /&gt;
  
      /// &lt;reference path="jasmine/jasmine.d.ts"/&gt;
  </code></pre>
  
  <p>I am quite new to this, but it suppose grunt should take code from referenced files and compile it into target .js file, but it doesn't. It just generates files with reference rows...</p>