Use newer Zend Framework components; raise PHP requirement. (#598)

.travis.yml

 sudo: false
 language: php
 php:
-  - 5.4
-  - 5.5
   - 5.6
   - 7.0
+  - 7.1
 
 env:
   - VUFIND_HOME=$PWD VUFIND_LOCAL_DIR=$PWD/local

composer.json

@@ -28,10 +28,34 @@
         "vufind-org/vufindharvest": "2.2.0",
         "vufind-org/vufindhttp": "2.1.1",
         "yajra/laravel-pdo-via-oci8": "1.1.1",
-        "zendframework/zendframework": "2.4.6",
+        "zendframework/zend-cache": "2.7.2",
+        "zendframework/zend-captcha": "2.6.0",
+        "zendframework/zend-code": "2.6.3",
+        "zendframework/zend-config": "2.6.0",
+        "zendframework/zend-console": "2.6.0",
+        "zendframework/zend-crypt": "2.6.0",
+        "zendframework/zend-db": "2.8.2",
+        "zendframework/zend-dom": "2.6.0",
+        "zendframework/zend-escaper": "2.5.2",
+        "zendframework/zend-eventmanager": "2.6.3",
+        "zendframework/zend-feed": "2.5.2",
+        "zendframework/zend-http": "2.5.5",
+        "zendframework/zend-i18n": "2.7.3",
+        "zendframework/zend-loader": "2.5.1",
+        "zendframework/zend-log": "2.9.1",
+        "zendframework/zend-mail": "2.7.1",
+        "zendframework/zend-modulemanager": "2.7.2",
+        "zendframework/zend-mvc": "2.6.3",
+        "zendframework/zend-paginator": "2.7.0",
+        "zendframework/zend-servicemanager": "2.7.5",
+        "zendframework/zend-session": "2.7.3",
+        "zendframework/zend-soap": "2.6.0",
+        "zendframework/zend-stdlib": "2.7.7",
+        "zendframework/zend-validator": "2.8.1",
+        "zendframework/zend-view": "2.8.1",
         "zendframework/zendrest": "2.0.2",
         "zendframework/zendservice-amazon": "2.0.4",
-        "zf-commons/zfc-rbac": "2.5.2"
+        "zf-commons/zfc-rbac": "2.5.3"
     },
     "require-dev": {
         "behat/mink": "1.7.0",