title: Gulp-sass and browser-sync don't reload browser
body: <p>When I change some scss file everything seems to work (scss is compiled to css file and the source files are watched):</p>
  
  <pre><code>[21:19:46] Starting 'sass'...
  [BS] 1 file changed (principal.css)
  [21:19:46] Finished 'sass' after 18 ms
  </code></pre>
  
  <p>But I need to reload the browser by hand to reflect the changes. This is my gulpfile:</p>
  
  <pre><code>var gulp        = require('gulp');
  var browserSync = require('browser-sync').create();
  var sass        = require('gulp-sass');
  
  // Static Server + watching scss/html files
  gulp.task('default', ['sass'], function() {
  
      browserSync.init({
          proxy: "huertajalon/"
      });
  
      gulp.watch("./sass/**/*.scss", ['sass']);
      gulp.watch("./*.php").on('change', browserSync.reload);
      gulp.watch("./style.css").on('change', browserSync.reload);
  
  });
  
  // Compile sass into CSS &amp; auto-inject into browsers
  gulp.task('sass', function() {
      return gulp.src("sass/principal.scss")
          .pipe(sass())
          .pipe(gulp.dest("./css"))
          .pipe(browserSync.stream());
  });
  </code></pre>
  
  <p>In other cases (for example, when I modify and save style.css) the browser reloads well.</p>
  
  <p>What am I doing wrong? Thanks!</p>