Squashed commit of the following:

commit 33ad1ab
Author: Srivats P <[email protected]>
Date:   Wed Jan 4 18:21:07 2017 +0530

    Make osx_image global

commit d90a99f
Author: Srivats P <[email protected]>
Date:   Tue Jan 3 22:21:02 2017 +0530

    include not exclude the osx image

commit 4038ca8
Author: Srivats P <[email protected]>
Date:   Tue Jan 3 21:36:46 2017 +0530

    Fix osx_image location again

commit 232dfdb
Author: Srivats P <[email protected]>
Date:   Tue Jan 3 21:16:15 2017 +0530

    Fix incorrect location of overriding osx_image

commit 00a487c
Author: Srivats P <[email protected]>
Date:   Tue Jan 3 20:58:09 2017 +0530

    Force sierra instead of el-capitan

    See cartr/homebrew-qt4#7

commit 33c39b8
Author: Srivats P <[email protected]>
Date:   Tue Jan 3 20:37:26 2017 +0530

    Troubleshoot osx build break changeset pstavirs#4

commit 8d16809
Author: Srivats P <[email protected]>
Date:   Tue Jan 3 19:03:56 2017 +0530

    Troubleshoot Travis OSX build break changeset pstavirs#3

commit ae149d0
Author: Srivats P <[email protected]>
Date:   Tue Jan 3 18:24:51 2017 +0530

    troubleshoot osx build break - changeset pstavirs#2

commit 2626339
Author: Srivats P <[email protected]>
Date:   Tue Jan 3 18:11:46 2017 +0530

    debug changes to troubleshoot osx build break

commit f3423b7
Author: Srivats P <[email protected]>
Date:   Sun Jan 1 12:49:57 2017 +0530

    Use latest protobuf version in HomeBrew

    We had reverted to using protobuf 2.6 when protobuf 3.0 had a regression
    issue with respect to RPCs - this has been fixed in v3.1.0

.travis.yml

@@ -1,4 +1,5 @@
 language: cpp
+osx_image: xcode8.2
 
 os:
   - linux
@@ -14,7 +15,7 @@ matrix:
       compiler: gcc
 
 before_install:
-  - "if [ $TRAVIS_OS_NAME = 'osx' ]; then brew update && brew install qt && brew install protobuf260; fi"
+  - "if [ $TRAVIS_OS_NAME = 'osx' ]; then brew update && brew tap cartr/qt4 && brew tap-pin cartr/qt4 && brew install qt && brew install protobuf && ls -lR /usr/local/include; fi"
 
 addons:
   apt: