Modify travis to build HDF5

Author: ranjanan

.travis.yml

@@ -17,10 +17,10 @@ matrix:
   - julia: nightly
 
 ## uncomment and modify the following lines to manually install system packages
-#addons:
-#  apt: # apt-get for linux
-#    packages:
-#    - gfortran
+addons:
+  apt: # apt-get for linux
+    packages:
+    - hdf5-tools
 #before_script: # homebrew for mac
 #  - if [ $TRAVIS_OS_NAME = osx ]; then brew install gcc; fi