Fixed typo in .ruby-version.sample
Merge pull request #7 from mighe/master

Thread safe observers
Merge branch 'master' of github.com:jdantonio/concurrent-ruby
Wrote pending specs for Future#execute refactor
Implemented Future.execute and Future#execute
Removed superflous *args from Future.new
Updated Future documentation.
Implemented ScheduledTask.execute and ScheduledTask#execute
Updated ScheduledTask documentation
Future.new throws an exception when no block given, just like ScheduledTask.
Future and ScheduledTask both support Dereferenceable.
Fixed code indentation.
Updated documentation.
Fixed broken Future tests.
Less brittle spec