splitting the low-level tbox and abox tests; adding a
getInstanceTaxonomyQuietly method to the reasoner state
remove unnecessary try-catch
setting up incremental ABox tests, some refactoring to re-use as much
code as possible
fixed the incremental change loader which must always add axioms and
only then delete them. various other tweaks
some optimization to the acyclicity/reduction taxonomy validator
Merge branch 'master' into feature/stages

Conflicts:
	elk-reasoner/src/main/java/org/semanticweb/elk/reasoner/stages/AbstractReasonerState.java