Replace propagateAsDecision() with Theory::getNextDecisionRequest():

Replace propagateAsDecision() with Theory::getNextDecisionRequest():

* arrays now uses the new approach by using a CDQueue<>
* uf strong solver has had the feature disabled, pending a merge from Andy
* theory kinds files now have a getNextDecisionRequest property (if you want to take part in such decision requests you have to list that property)
* the staticLearning property has been renamed ppStaticLearn to match the function name
* theory kinds files are now checked again for correctly-declared properties (this had been disabled)
* minor documentation and other fixups