title: Gulp compiled css files are empty
body: <p>I am new to Gulp, i use it in VS2015, with TaskRunnerExplorer.</p>
  
  <p>This is the config files with the paths:</p>
  
  <pre><code>    config = {
  
  base: '',
  webRoot: rootPath,
  paths: {
      source: {
          js: rootPath + 'Views/**/*.js',
          bundleJs: rootPath + 'wwwroot/scripts/app/**/*.js',
          minJs: rootPath + '**/*.min.js',
          testJs: rootPath + '**/*.test.js',
          e2eJs: rootPath + '**/*.spec.js',
          bundleScss: rootPath + 'wwwroot/css/src/**/*.scss',// where the bundled scss files are
          viewsScss: rootPath + 'Views/**/*.scss', // where the individual scss of each subfolder of Views folder
          bundleCss: rootPath + 'Views/bundledcss.style.min.css', //the unique file that agregates the min.css files
          viewsCss: rootPath + 'Views/**/*.min.css',
          minCss: rootPath + 'wwwroot/css/**/*.min.css', // the minified css path
          libCss: rootPath + 'wwwroot/css/lib/*.css',
          libJs: rootPath + 'wwwroot/scripts/lib/*.js'
      },
      output: {
          js:{
              bundle: rootPath + 'Views',
              views: rootPath + 'Views'
          },
          css:{
              bundle: rootPath + 'Views',
              views: rootPath + 'Views'
          },
          lib: {
              js:rootPath + 'wwwroot/scripts/lib',
              css: rootPath + 'wwwroot/css/lib',
              font: rootPath + 'wwwroot/css/fonts/'
          }
      },
  </code></pre>
  
  <p>This is the gulp file (partial)</p>
  
  <pre><code>var gulp    = require('gulp'),
  
  //Node modules
  console         = require('better-console'),
  
  // gulp plugins
  sass            = require('gulp-sass'),
  rename          = require('gulp-rename'),
  autoprefixer    = require('gulp-autoprefixer'),
  minifyCss       = require('gulp-minify-css'),
  plumber         = require('gulp-plumber'),
  gulpif          = require('gulp-if'),
  
  
  // Configuration
  config  = require('../../config');
  
  module.exports = function(isRelease) {
  return function () {
      var stream = gulp.src(config.paths.source.viewsScss) 
          .pipe(plumber())
          .pipe(sass().on('error', sass.logError))
          .pipe(autoprefixer())               
          .pipe(gulpif(isRelease,minifyCss()))
          .pipe(rename(config.rename.minCSS)) 
          .pipe(gulp.dest(config.paths.output.css.views));
  
      return stream;
  };
  };
  </code></pre>
  
  <p>I want to compile the sass files in each subfolder of the Views folder, however the min.css files generated in each subfolder is empty. Did i miss a step? Thank you in advance.</p>