Remove outdated special operators

Follow ticket-9048
See below links

* http://bugs.ruby-lang.org/issues/9048
* https://github.com/ruby/ruby/pull/383#issuecomment-26915103
Fixed running specs on MRI.
Simplified .travis.yml.

We need the same environment for Rubinius and MRI.
Merge remote-tracking branch 'kachick/remove_special_operators' into 2.0