Get rid of Postag#clean_analysis - too slow
Datapoints calculated completely now

With the recent deletion of clean_analysis we currently don't catch the
real value of all used postag datapoints.
Bypass #analysis in Postag#report

Little faster
Use a constant to get the datapoint containers

No need to recompute it all the time
Fix default attribute in Diff#to_xml
Fix check for jruby
Enable multi-threading for jruby