added 'lable' field to Entity data type. in this snd attempt, a constructor is employed for better maintainability
added labelMap to OWL2.Sign, to store class labels within this field during analysis
labels are extracted from annotations and stored in respective field (Sign.labelMap). however they are never printed or otherwise employed as of now
labels are properly written in OWL2.Sign.symOf and are printed via Static.ToXml, using the new Logic.Logic.sym_label
removed comments; version for reviewing
implemented OWL2.AS.pairSymbols, and did run scan and fixed stuff
test for 'prefix=rdfs' when extracting labels
Merge pull request #1382 from spechub/1241-OBO-Symbol-Names

1241 obo symbol names