add .travis.yml

.travis.yml

+language: cpp
+
+sudo: false
+
+script:
+        - mkdir build
+        - cd build
+        - cmake -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=OFF -DLLVM_TARGETS_TO_BUILD="all" -G "Unix Makefiles" ..
+        - make -j 8
+
+compiler:
+        - clang
+        - gcc
+
+os:
+        - osx