Fix Coveralls reports, now really tracks code coverage
Fix Coveralls reports, now really tracks code coverage

Before, `Bundler.require` was executed before `Coveralls.wear!` was
called, therefore no actual code coverage was tracked. Instead
'invokations' of code within the spec folder was analyzed.

Also, now only Rubinius gets excluded from generating Coveralls reports,
MRI and JRuby work smoothly.

nicolas-fricke/youyouaidi