increasing python version from 3.3 to 3.4 for numpy 1.12 compatability

.travis.yml

@@ -12,7 +12,7 @@ cache:
 language: python
 python:
   - "2.7"
-  - "3.3"
+  - "3.4"
 
 # NB:
 # In before_install and install sections below,