Travis and spec changes

1. Updated Gemfiles to support multiple VMs - MRI, JRuby, Rubinius
2. Removed .lock files to allow appropriate .lock files to be built for each VM in the CI run.
3. Updated specs to be RSpec 3.0 compatible - eliminated use of 'its', 'be_true', and 'be_false'.
4. Removed .ruby-version.
5. Added Ruby 2.1.0, JRuby, and Rubinius to Travis config.