use newer numpy, as 1.8.1 has a broken dependency on conda.

.travis.yml

@@ -13,7 +13,7 @@ env:
     # This environment tests the oldest supported anaconda env
     - DISTRIB="conda" PYTHON_VERSION="2.7" NUMPY_VERSION="1.7.1"
     # This environment tests the newest supported anaconda env
-    - DISTRIB="conda" PYTHON_VERSION="3.4" NUMPY_VERSION="1.8.1"
+    - DISTRIB="conda" PYTHON_VERSION="3.4" NUMPY_VERSION="1.10.1"
 install: source continuous_integration/install.sh
 cache: apt
 script: nosetests