Build steps moved to script.

.travis.yml

           sources: *sources
 
 script:
-    - if [[ "$CXX" == clang* ]]; then export CXXFLAGS="-stdlib=libc++"; fi
-    - mkdir build && cd build
-    - cmake ..
-    - make
-    - make unittest
-
-
+    - script/ci_build.sh
 

script/ci_build.sh

+#!/bin/bash
+
+if [[ "$CXX" == clang* ]]; then
+    export CXXFLAGS="-stdlib=libc++"
+fi
+
+mkdir build && cd build
+
+cmake ..
+make
+make unittest
+