Revert "Revert "Upgrade to ruby 2.1.2""

This reverts commit 4016bcd7b1bbc8a0165e8b0728d349829de03fda.
Revert "Revert "Reverting mysql to 0.3.13 due to "undefined symbol" issue during deploy""

This reverts commit 9e6f6524bfb184b1ff2550df0950c5b8893ac3ba.
Downgrade pg and newrelic_rpm
update deps and lock rubocop to 0.18.1
Bump to ruby 2.1.3

[#70710962]
Lock mysql version to 0.3.13

- later versions cause errors on deploy
- we should fix this after getting CC to work on ruby 2.1 generally

[#70710962]
Downgrade pg and newrelic_rpm
Change Gemfile to use 'github:' for the github hosted gems

- This changes the remote to use the git:// protocol