Add OSX build to Travis matrix

Also allow the Linux build to fail, for now

.travis-install-deps.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+if [[ $TRAVIS_OS_NAME == 'osx' ]]; then
+	brew install scons sfml boost
+else
+	sudo apt-get update -qq
+	sudo apt-get install -qq libsfml-dev libboost-dev
+fi

.travis.yml

@@ -6,12 +6,22 @@ script: scons
 compiler:
  - clang
 
-sudo: required
-dist: trusty
+os:
+ - linux
+ - osx
+
+matrix:
+ allow_failures:
+  - os: linux
+ include:
+  - os: linux
+    sudo: required
+    dist: trusty
+  - os: osx
+    osx_image: xcode7.2
 
 install:
- - sudo apt-get update -qq
- - sudo apt-get install -qq libsfml-dev libboost-dev
+ - ./.travis-install-deps.sh
 
 branches:
  except: