Update .travis.yml

Author: panesofglass

.travis.yml

@@ -1,10 +1,21 @@
 language: csharp
 
-mono: 
-  - latest 
-  - 4.0.5 
-
-sudo: false  # use the new container-based Travis infrastructure 
+matrix:
+  include:
+    - os: linux # Ubuntu 14.04
+      dist: trusty
+      sudo: required
+      dotnet: 2.0.0
+    - os: osx # OSX 10.11
+      osx_image: xcode7.2
+      dotnet: 2.0.0
+    - os: osx # OSX 10.12
+      osx_image: xcode7.3
+      dotnet: 2.0.0
 
 script: 
   - ./build.sh All
+
+branches:
+  except:
+    - gh-pages