reverting the number of iterations and rounds to the normal values
finally, class and instance taxonomies fully separated. now, this shiny
new stuff needs testing.
the new implementation of ConcurrentInstanceTaxonomy, which can properly
incapsulate any class taxonomy, passes our unit tests
avoid using specific implementation classes when init'ing the class and
the instance taxonomy states. incremental class taxonomy computation
stage no longer a subclass of the class taxonomy computation stage
implemented instance taxonomy cleaning for incremental ABoxes. Now it
passes our basic tests but more are needed.