fix travis config

.travis.yml

@@ -1,8 +1,21 @@
-language: C++
+language: cpp
-compiler:
-- clang
-- gcc
 script:
-- mkdir build/cmake/build && cd build/cmake/build && cmake .. && make && cd ../../../bin && xlnt.test
+  - mkdir build/cmake/build && cd build/cmake/build && cmake .. && make && cd ../../../bin && xlnt.test
+compiler:
+  - clang
+  - gcc
+install:
+  - if [ "$CXX" = "g++" ]; then export CXX="g++-4.8" CC="gcc-4.8"; fi
+addons:
+  apt:
+    sources:
+    - ubuntu-toolchain-r-test
+    packages:
+    - gcc-4.8
+    - g++-4.8
+    - clang
+notifications:
+  email: false
+sudo: false