Update devDependencies, gems and lots of cleanup/build fixes.

* switch to grunt-postcss and autoprefixer directly; this is the recommended way.
* uglify: specify `ie8` for compatibility
* specify `cascade:false` for autoprefixer
* specify `ieCompat` for less
* drop grunt-contrib-compress since it doesn't work with Node.js 10.x
* remove grunt-contrib-htmlmin to match the v4 docs
* clean up Gruntfile.js
* clean up .travis.yml and backport changes from v4
* build ie10-viewport-bug-workaround.less since it's used in examples
* move shrinkwrap to root
* bs-commonjs-generator.js: Use `path.posix`
* remove .hound.yml
* remove references to no longer used PR bots
* backport and adapt the sri generation script from v4

grunt/bs-commonjs-generator.js

@@ -16,7 +16,7 @@ module.exports = function generateCommonJSModule(grunt, srcFiles, destFilepath)
   var destDir = path.dirname(destFilepath);
 
   function srcPathToDestRequire(srcFilepath) {
-    var requirePath = path.relative(destDir, srcFilepath).replace(/\\/g, '/');
+    var requirePath = path.posix.relative(destDir, srcFilepath);
     return 'require(\'' + requirePath + '\')';
   }
 

grunt/configBridge.json

@@ -1,21 +1,21 @@
 {
   "paths": {
     "customizerJs": [
-      "/docs/3.4/assets/js/vendor/autoprefixer.js",
-      "/docs/3.4/assets/js/vendor/less.min.js",
-      "/docs/3.4/assets/js/vendor/jszip.min.js",
-      "/docs/3.4/assets/js/vendor/uglify.min.js",
-      "/docs/3.4/assets/js/vendor/Blob.js",
-      "/docs/3.4/assets/js/vendor/FileSaver.js",
-      "/docs/3.4/assets/js/raw-files.min.js",
-      "/docs/3.4/assets/js/src/customizer.js"
+      "../assets/js/vendor/autoprefixer.js",
+      "../assets/js/vendor/less.min.js",
+      "../assets/js/vendor/jszip.min.js",
+      "../assets/js/vendor/uglify.min.js",
+      "../assets/js/vendor/Blob.js",
+      "../assets/js/vendor/FileSaver.js",
+      "../assets/js/raw-files.min.js",
+      "../assets/js/src/customizer.js"
     ],
     "docsJs": [
-      "/docs/3.4/assets/js/vendor/holder.min.js",
-      "/docs/3.4/assets/js/vendor/clipboard.min.js",
-      "/docs/3.4/assets/js/vendor/anchor.min.js",
-      "/docs/3.4/assets/js/src/application.js",
-      "/docs/3.4/assets/js/src/search.js"
+      "../assets/js/vendor/holder.min.js",
+      "../assets/js/vendor/clipboard.min.js",
+      "../assets/js/vendor/anchor.min.js",
+      "../assets/js/src/application.js",
+      "../assets/js/src/search.js"
     ]
   },
   "config": {

grunt/generate-sri.js

@@ -0,0 +1,62 @@
+#!/usr/bin/env node
+
+'use strict';
+
+/*!
+ * Script to generate SRI hashes for use in our docs.
+ * Remember to use the same vendor files as the CDN ones,
+ * otherwise the hashes won't match!
+ *
+ * Copyright 2017-2018 The Bootstrap Authors
+ * Copyright 2017-2018 Twitter, Inc.
+ * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
+ */
+
+var crypto = require('crypto');
+var fs = require('fs');
+var path = require('path');
+var replace = require('replace-in-file');
+
+var configFile = path.join(__dirname, '../_config.yml');
+
+// Array of objects which holds the files to generate SRI hashes for.
+// `file` is the path from the root folder
+// `configPropertyName` is the _config.yml variable's name of the file
+var files = [
+  {
+    file: 'dist/css/bootstrap.min.css',
+    configPropertyName: 'css_hash'
+  },
+  {
+    file: 'dist/css/bootstrap-theme.min.css',
+    configPropertyName: 'css_theme_hash'
+  },
+  {
+    file: 'dist/js/bootstrap.min.js',
+    configPropertyName: 'js_hash'
+  }
+];
+
+files.forEach(function (file) {
+  fs.readFile(file.file, 'utf8', function (err, data) {
+    if (err) {
+      throw err;
+    }
+
+    var algo = 'sha384';
+    var hash = crypto.createHash(algo).update(data, 'utf8').digest('base64');
+    var integrity = algo + '-' + hash;
+
+    console.log(file.configPropertyName + ': ' + integrity);
+
+    try {
+      replace.sync({
+        files: configFile,
+        from: new RegExp('(\\s' + file.configPropertyName + ':\\s+"|\')(\\S+)("|\')'),
+        to: '$1' + integrity + '$3'
+      });
+    } catch (error) {
+      console.error('Error occurred:', error);
+    }
+  });
+});