Clean up the execution of RSpecs to run the platform-specific tests in the right place
Add JRuby to the list of rubies we should test on
Avoid building the C extension on JRuby
Remove support for Ruby 1.8.7

It's like, a million times dead. Concurrent Ruby won't support it which forces our hand though.
Merge pull request #43 from rtyler/platform-specific-specs

Clean up RSpecs to run the platform-specific tests in the right runtime