Updates RSpec so that tests run correctly on 1.9.3-p194

* I also had to upgrade jeweler to make it play nicely with my version
  of bundler. Newer versions of jeweler lock to bundler '~>1.0' instead
  of '~>1.0.0'

More details about the fix in RSpec at https://github.com/rspec/rspec-core/pull/258