Add missing module dependencies to install step

Author: paultcochrane

.travis.yml

@@ -10,6 +10,8 @@ install:
     - git clone https://github.com/tadzik/rakudobrew ~/.rakudobrew
     - rakudobrew build moar
     - rakudobrew build-panda
+    - panda install URI
+    - panda install Pod::To::HTML
 
 script:
     - make test