added clang

.travis.yml

@@ -2,13 +2,13 @@ language: cpp
 
 sudo: false
 
-compiler:
-  - gcc
-
 env:
-  - COMPILER=g++-4.8
   - COMPILER=g++-4.9
   - COMPILER=g++-5
+  - COMPILER=clang-3.4
+  - COMPILER=clang-3.5
+  - COMPILER=clang-3.6
+  - COMPILER=clang-3.7
 
 addons:
   apt:
@@ -18,6 +18,10 @@ addons:
     - g++-4.8
     - g++-4.9
     - g++-5
+    - clang-3.4
+    - clang-3.5
+    - clang-3.6
+    - clang-3.7
     - valgrind
     - python-pip
     - python-yaml