var gulp = require('gulp'),
    fs = require("fs"),
    concat = require('gulp-concat'),
    postcss = require('gulp-postcss'),
    replace = require('gulp-replace'),
    cssnext = require("gulp-cssnext"),
    mixins = require('postcss-mixins'),
    imagemin = require('gulp-imagemin'),
    pngquant = require('imagemin-pngquant'),
    notify = require('gulp-notify'),
    autogrid = require('autogrid'),
    include = require('postcss-include')

// Grid editor
  gulp.task('grid', function() {
    var css = autogrid({
      columns: 12,
      gutter: '20px',
      container: '1700px'
    });
    fs.writeFileSync('src/css/grid.css', css);
  });

// compile CSS
  gulp.task('styles', function() {
    return gulp.src('src/css/style.css')
      .pipe(postcss([
        require('postcss-import')({path: ['bower_components'], from: 'src/css/style.css'}),
        require('postcss-mixins'),
        require('postcss-simple-vars'),
        require('postcss-nested'),
        require('postcss-include'),
        require('autoprefixer-core')({ browsers: ['last 2 versions', '> 2%'] })
        
      ]))
      .pipe(cssnext())
      // .pipe(include({ css: 'src/css/style.css' }))
      .pipe(gulp.dest('build/css/'))
      .pipe(notify({ message: 'Styles task complete' }))
  });

// compile HTML
  gulp.task('minify', function() {
    return gulp.src('src/**/*.php')
      .pipe(gulp.dest('build'))
      .pipe(notify({ message: 'HTML compile finished' }))
  });


// Images
  gulp.task('images', function() {
    return gulp.src('src/img/**/*')
      .pipe(imagemin({ optimizationLevel: 3, progressive: true, interlaced: true }))
      .pipe(gulp.dest('build/img'))
      .pipe(notify({ message: 'Images task complete' }));
  });
 

// Compile scripts
  gulp.task('scripts', function() {
    return gulp.src([
      'bower_components/**/*.min.js', 
      'src/js/scripts.js'])
      .pipe(concat('scripts.min.js'))
      .pipe(gulp.dest('build/js'))
      .pipe(notify({ message: 'Javascript compiled' }));
  });

// Replace
  gulp.task('replace', ['minify'], function(){

  });
// Watch
  gulp.task('watch', function() {
   
    // Watch .scss files
    gulp.watch('src/css/**/*.css', ['styles']);
   
    //Watch .js files
    gulp.watch('src/js/**/*.js', ['scripts']);
   
    // Watch image files
    gulp.watch('src/img/**/*', ['images']);

    // Watch php files
    gulp.watch('src/*.php', ['replace']);
   
    // Create LiveReload server
    // livereload.listen();
   
    // Watch any files in build/, reload on change
    // gulp.watch(['/']).on('change', livereload.changed);
   
  });
 // Build project
  gulp.task('build', [
    'styles', 
    'minify',
    'scripts',
    'images'
  ]);
@@ -911,269 +911,93 @@
 css-
-simple-vars'),%0A        require('postcss-nested'),%0A        require('postcss-include'),%0A        require('autoprefixer-core')(%7B browsers: %5B'last 2 versions', '%3E 2%25'%5D %7D)%0A        %0A      %5D))%0A      .pipe(cssnext())%0A      // .pipe(include(%7B css: 'src/css/style.css' %7D))
+nested')     %0A      %5D))%0A      .pipe(cssnext()) // Autoprefixer is included in cssnext
 %0A   

Remove redundant includes