Update devDependencies and gems.

Also:

* switch to `devDependencies`
* switch to @lodder/grunt-postcss since grunt-postcss is abandoned
* remove css-mqpacker since it's no longer maintained
* add wdm gem for Windows since it's recommended

Gemfile

@@ -1,8 +1,9 @@
 source 'https://rubygems.org'
 
-gem 'jekyll', '~> 3.8.4'
-gem 'jekyll-avatar', '~> 0.6.0'
+gem 'jekyll', '~> 3.8.6'
+gem 'jekyll-avatar', '~> 0.7.0'
 gem 'jekyll-email-protect', '~> 1.0.3'
-gem 'jekyll-feed', '~> 0.11.0'
+gem 'jekyll-feed', '~> 0.12.1'
 gem 'jekyll-paginate', '~> 1.1.0'
-gem 'jekyll-sitemap', '~> 1.2.0'
+gem 'jekyll-sitemap', '~> 1.3.1'
+gem 'wdm', '~> 0.1.1', :install_if => Gem.win_platform?

Gemfile.lock

@@ -1,22 +1,22 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.5.2)
-      public_suffix (>= 2.0.2, < 4.0)
+    addressable (2.7.0)
+      public_suffix (>= 2.0.2, < 5.0)
     colorator (1.1.0)
-    concurrent-ruby (1.0.5)
+    concurrent-ruby (1.1.5)
     em-websocket (0.5.1)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0.6.0)
     eventmachine (1.2.7)
     eventmachine (1.2.7-x64-mingw32)
-    ffi (1.9.25)
-    ffi (1.9.25-x64-mingw32)
+    ffi (1.11.1)
+    ffi (1.11.1-x64-mingw32)
     forwardable-extended (2.6.0)
     http_parser.rb (0.6.0)
     i18n (0.9.5)
       concurrent-ruby (~> 1.0)
-    jekyll (3.8.4)
+    jekyll (3.8.6)
       addressable (~> 2.4)
       colorator (~> 1.0)
       em-websocket (~> 0.5)
@@ -29,51 +29,51 @@ GEM
       pathutil (~> 0.9)
       rouge (>= 1.7, < 4)
       safe_yaml (~> 1.0)
-    jekyll-avatar (0.6.0)
-      jekyll (~> 3.0)
+    jekyll-avatar (0.7.0)
+      jekyll (>= 3.0, < 5.0)
     jekyll-email-protect (1.0.3)
-    jekyll-feed (0.11.0)
-      jekyll (~> 3.3)
+    jekyll-feed (0.12.1)
+      jekyll (>= 3.7, < 5.0)
     jekyll-paginate (1.1.0)
     jekyll-sass-converter (1.5.2)
       sass (~> 3.4)
-    jekyll-sitemap (1.2.0)
-      jekyll (~> 3.3)
-    jekyll-watch (2.1.1)
+    jekyll-sitemap (1.3.1)
+      jekyll (>= 3.7, < 5.0)
+    jekyll-watch (2.2.1)
       listen (~> 3.0)
     kramdown (1.17.0)
-    liquid (4.0.1)
-    listen (3.1.5)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
-      ruby_dep (~> 1.2)
+    liquid (4.0.3)
+    listen (3.2.0)
+      rb-fsevent (~> 0.10, >= 0.10.3)
+      rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.3.6)
-    pathutil (0.16.1)
+    pathutil (0.16.2)
       forwardable-extended (~> 2.6)
-    public_suffix (3.0.3)
+    public_suffix (4.0.1)
     rb-fsevent (0.10.3)
-    rb-inotify (0.9.10)
-      ffi (>= 0.5.0, < 2)
-    rouge (3.3.0)
-    ruby_dep (1.5.0)
-    safe_yaml (1.0.4)
-    sass (3.6.0)
+    rb-inotify (0.10.0)
+      ffi (~> 1.0)
+    rouge (3.12.0)
+    safe_yaml (1.0.5)
+    sass (3.7.4)
       sass-listen (~> 4.0.0)
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
+    wdm (0.1.1)
 
 PLATFORMS
   ruby
   x64-mingw32
 
 DEPENDENCIES
-  jekyll (~> 3.8.4)
-  jekyll-avatar (~> 0.6.0)
+  jekyll (~> 3.8.6)
+  jekyll-avatar (~> 0.7.0)
   jekyll-email-protect (~> 1.0.3)
-  jekyll-feed (~> 0.11.0)
+  jekyll-feed (~> 0.12.1)
   jekyll-paginate (~> 1.1.0)
-  jekyll-sitemap (~> 1.2.0)
+  jekyll-sitemap (~> 1.3.1)
+  wdm (~> 0.1.1)
 
 BUNDLED WITH
-   1.16.6
+   1.17.3

Gruntfile.js

@@ -1,6 +1,10 @@
 'use strict';
 
 module.exports = function(grunt) {
+    // Load any grunt plugins found in package.json.
+    require('load-grunt-tasks')(grunt);
+    require('time-grunt')(grunt);
+
     grunt.initConfig({
         dirs: {
             dest: '_site',
@@ -94,7 +98,6 @@ module.exports = function(grunt) {
         postcss: {
             options: {
                 processors: [
-                    require('css-mqpacker')(), // combine media queries
                     require('postcss-combine-duplicated-selectors')({ removeDuplicatedProperties: true }), // combine duplicate selectors
                     require('autoprefixer')() // add vendor prefixes
                 ]
@@ -299,10 +302,6 @@ module.exports = function(grunt) {
 
     });
 
-    // Load any grunt plugins found in package.json.
-    require('load-grunt-tasks')(grunt, { scope: 'dependencies' });
-    require('time-grunt')(grunt);
-
     var buildTasks = [
         'clean',
         'jekyll',

README.md

@@ -2,7 +2,7 @@
 
 [![Linux Build Status](https://img.shields.io/travis/mpc-hc/mpc-hc.org/master.svg?label=Linux%20build)](https://travis-ci.org/mpc-hc/mpc-hc.org)
 [![Windows Build Status](https://img.shields.io/appveyor/ci/XhmikosR/mpc-hc-org/master.svg?label=Windows%20build)](https://ci.appveyor.com/project/XhmikosR/mpc-hc-org/branch/master)
-[![dependencies Status](https://img.shields.io/david/mpc-hc/mpc-hc.org.svg)](https://david-dm.org/mpc-hc/mpc-hc.org)
+[![devDependencies Status](https://img.shields.io/david/dev/mpc-hc/mpc-hc.org.svg)](https://david-dm.org/mpc-hc/mpc-hc.org?type=dev)
 
 ## Getting started