Replace PelletListener with a TBoxReasonerModule in the Application.
The reasoner will be accessible only through here, not as a context attribute or through the WebappDaoFactory.
Split out the initialization of the TBox reasoner from SimpleReasonerSetup.
Break out the filtering of TBox changes into a ConfiguredReasonerListener.
Refactor the threading logic into a BasicTBoxReasonerDriver.
Add a factory for creating VitroBackgroundThreads in an Executor.
Isolate the actual reasoner into a TBoxReasoner implementation. In this case, PelletTBoxReasoner.
Combine the consistency flag, error flag, explanation, and running status into one TBoxReasonerStatus object.
