Update travis to allow failure on documentation job.

.travis.yml

@@ -1,18 +1,21 @@
 language: php
-php:
-  - '5.5'
+
 sudo: false
 env:
   global:
     - GIT_NAME: "'Couscous auto deploy'"
     - GIT_EMAIL: [email protected]
     - GH_REF: github.com/swisnl/jQuery-contextMenu
     - secure: XaE2bPODLwmzaNAKv9pA8mMiXJc8OrpyrO5tIGuOCwfQ+q7hx6Xa/tTcyn5+H2g+xYyJ0Qqv5+SDkDxbbgaVJLR1VEW15KEcZbD/3speqkg+yIC/oFxgbf1Ib01f0FowR2cw4/5Y2XzCM8CU7UxOLFGBDDCvM39Ab3UUl4uB/8g=
-  matrix:
-    - JQUERY=1
-    - JQUERY=2
-    - JQUERY=3
-    - DOCUMENTATION=1
+matrix:
+  include:
+    - env: JQUERY=1 php=5.5
+    - env: JQUERY=2 php=5.5
+    - env: JQUERY=3 php=5.5
+    - env: DOCUMENTATION=1 php=5.5
+  allow_failures:
+    - env: DOCUMENTATION=1 php=5.5
+
 
 install:
 - if [ "$JQUERY" ] ; then nvm install stable && npm install && npm install jquery@$JQUERY && npm test ; fi