Merge pull request #140 from OpenHMD/travis

Add Mac OSX build to travis

.travis.yml

@@ -1,15 +1,22 @@
 # This is the project file for the automated build system travis (travis-ci.com).
-sudo: required
-
-dist: trusty
+matrix:
+  include:
+    - os: linux
+      sudo: false
+      dist: trusty
+    - os: osx
 
 language: c
 
 compiler: gcc
 
+addons:
+  apt:
+    packages:
+      - libhidapi-dev
+
 before_install:
-  - sudo apt-get update -qq
-  - sudo apt-get install -qq libhidapi-dev
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew install hidapi; fi
   - ./autogen.sh
 
 install: true # skip install step