Disable linux builds as Boost sporadically fails to build in Travis

Author: Kent Knox

.travis.yml

@@ -17,8 +17,9 @@ language: cpp
 sudo: required # false
 
 # os: expands the build matrix to include multiple os's
+# disable linux, as we get sporadic failures on building boost, needs investigation
 os:
-  - linux
+#  - linux
   - osx
 
 # compiler: expands the build matrix to include multiple compilers (per os)