Added bower.json to bootstrap and jui extensions.

extensions/bootstrap/bower.json

+{
+    "name": "yii2-bootstrap",
+    "version": "2.0.0",
+    "homepage": "http://www.yiiframework.com/",
+    "authors": [
+        "Qiang Xue <qiang.xue@gmail.com>"
+    ],
+    "description": "The Twitter Bootstrap extension for the Yii framework",
+    "keywords": [
+        "yii2",
+        "bootstrap"
+    ],
+    "license": "BSD-3-Clause",
+    "ignore": [
+        "**/.*",
+        "**/*"
+    ],
+    "dependencies": {
+        "bootstrap": ">=3.0.0"
+    }
+}

extensions/jui/bower.json

+{
+    "name": "yii2-jui",
+    "version": "2.0.0",
+    "homepage": "http://www.yiiframework.com/",
+    "authors": [
+        "Qiang Xue <qiang.xue@gmail.com>"
+    ],
+    "description": "The Jquery UI extension for the Yii framework",
+    "keywords": [
+        "yii2", "Jquery UI"
+    ],
+    "license": "BSD-3-Clause",
+    "ignore": [
+        "**/.*",
+        "**/*"
+    ],
+    "dependencies": {
+        "jquery.ui": ">=1.10.0"
+    }
+}

extensions/jui/composer.json

 {
     "name": "yiisoft/yii2-jui",
     "description": "The Jquery UI extension for the Yii framework",
-	"keywords": ["yii2", "Jquery UI", "renderer"],
+    "keywords": ["yii2", "Jquery UI"],
     "type": "yii2-extension",
     "license": "BSD-3-Clause",
     "support": {
@@ -21,6 +21,8 @@
         "yiisoft/yii2": "*"
     },
     "autoload": {
-		"psr-4": { "yii\\jui\\": "" }
+        "psr-4": {
+            "yii\\jui\\": ""
+        }
     }
 }