Add PHP7 to travis

.travis.yml

@@ -1,14 +1,26 @@
 language: php
 sudo: require
-env:
-  - TEST_SUITE=1
-  - TEST_SUITE=2
-php:
-  - 5.5
-  - 5.6
 
 matrix:
   fast_finish: true
+  include:
+    - php: 5.5
+      env: TEST_SUITE=1
+    - php: 5.6
+      env: TEST_SUITE=1
+    - php: 7.0
+      env: TEST_SUITE=1
+    - php: 5.5
+      env: TEST_SUITE=2
+    - php: 5.6
+      env: TEST_SUITE=2
+    - php: 7.0
+      env: TEST_SUITE=2
+  allow_failures:
+    - php: 7.0
+      env: TEST_SUITE=1
+    - php: 7.0
+      env: TEST_SUITE=2
 
 services:
   - mysql