Do not save copy of NNF on  OWL axioms
Merge pull request #294 from sesuncedu/version4_no_nnf_cache

Do not save copy of NNF on  OWL axioms
Merge pull request #293 from sesuncedu/version4_trimming_to_size

Provide "trimToSize" methods on MapPointer, Internals, and OWLAxiomIndexImpl
Use singleton list if only single annotation is used.
Use singleton sets for first value; switch if second value is added.
Merge branch 'version4_singletons' into version4_memsave

Conflicts:
	impl/src/main/java/uk/ac/manchester/cs/owl/owlapi/OWLAxiomImpl.java
fix merged imports