Try a newer mpl due to Tkinter err on install

.travis.yml

@@ -49,8 +49,8 @@ before_install:
     - travis_retry pip install wheel;
     - if [[ $ENV != python=2.6* ]]; then
             travis_retry pip install --no-index --find-links=http://wheels.scikit-image.org/ matplotlib;
-      else 
-         pip install matplotlib==1.0.1;
+      else
+         pip install matplotlib==1.1.0;
       fi
     - python check_bento_build.py