Add 5.2 and use dist: precise.

Author: octalmage

.travis.yml

@@ -1,6 +1,8 @@
 language: php
+dist: precise
 
 php:
+  - 5.2
   - 5.3
   - 5.5
   - 5.6
@@ -10,6 +12,10 @@ env:
   - WP_VERSION=latest WP_MULTISITE=0
   - WP_VERSION=4.5 WP_MULTISITE=0
 
+matrix:
+  allow_failures:
+  - php: 5.2
+
 matrix:
   include:
     - php: 5.6