another try with travis

.travis.yml

@@ -5,17 +5,10 @@ dist: trusty
 addons:
   apt:
     sources:
-      - boost-latest
       - ubuntu-toolchain-r-test
     packages:
-      - gcc-5
-      - g++-5
-      - libboost1.56-all-dev
       - cmake
 
-env:
-    - CC=gcc-5 CXX=g++-5
-
 before_script:
   - mkdir build
   - cd build