Updated Ruby to 2.1.2, RSpec to 3, nokogiri to 1.6.2.1, and others.

[#74580252]
Improved replacement of errors_on to be more Rspec 3-ey.

[#74580252]
Merge branch 'upgrade_ruby_74580252' of github.com:moggyboy/predictionbook into moggyboy-upgrade_ruby_74580252
Merge branch 'moggyboy-upgrade_ruby_74580252'
Merge pull request #1 from tricycle/master

Incorporate updates to Ruby and gems