Added support for xcode 8.x

[karnikad]

Modified the code to make it work with xcode 8.x. Had to make the
following changes:

1. Changed the xcode version check to now allow Xcode 8.x
2. Added --allow-unrelated-histories flag to git as git 2.11 is shipped
   with mac os x sierra and the previous command was failing here.

Fixes #41 and #42

[karnikad]

@misterfifths can you please help me with this PR. Seems like the tests have timed out. I don't know whether it is due to the TravisCI configuration. They have now xcode 7.3.1 images from November 2016.

[misterfifths]

Hey! This looks great! Sorry for the delay.. it's been a crazy week. I'll take a look at the Travis situation tomorrow. Thanks for your work!

[misterfifths]

Hm.. well, not the most scientific approach, but I did a few things and got it working:

• Switched to the xcode8.1 image for Travis
• Switched from xctool back to xcodebuild. xctool's build functionality is apparently deprecated.
• Updated xcconfigs and Cocoapods integration

The branch is here: https://github.com/crushlovely/Amaro/tree/karnikad-master. Probably what makes sense is for you to merge that into your fork, which will update this PR. From your clone of your fork, something like this:

$ git remote add upstream https://github.com/crushlovely/Amaro.git
$ git fetch upstream
$ git merge upstream/karnikad-master
# make sure everything is to your liking for the PR, and then:
$ git push

Thanks again!

[misterfifths]

👍 Looks good to me! All merged.

[karnikad]

Thank you for the merge.