Add travis run on osx server

Author: mrjosh

.travis.yml

@@ -4,9 +4,12 @@ php:
  - 7.0
  - hhvm
 
+os:
+ - osx
+
 before_install:
- - brew update
- - brew install phantomjs
+ - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew update ; fi
+ - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew install phantomjs; fi
  - export PHANTOMJS_BINARY_PATH=$(which phantomjs)
 
 script: