Use Optional a better way to throw an exception
Use ReactorFactory in the test
Extract api folder from jeactor-core into jeactor-api
Build Pattern :: Context : implemented and tested
Revert "Build Pattern :: Context : implemented and tested"

This reverts commit 6af2d26cc36dc490fdbeaa9787434e0cc0be4ac7.
Use delegator methods in reactor for shutdown and awaitTermination
Update registration with fluent API pattern
Remove useless Optional usage in Action and Reactor
Added fluent API pattern