* Added words "join" function in TextConversion

* Added expander support to wordsToIdentifiers method in TextConversion
* Added getter methods for retrieving sub distances in RankedAbstractMetaObject
* Added getter methods for attributes in RankedSortedDistFunctionCollection
* Reranking collection is now memorizing the data only in addAll
* KNN Approximation operation now uses "structure default" parameter by default
* Added time statistics for changing the operation answer collection
* Extended the time statistics with the user and cpu (user + system) times - currently works only for one thread
* Few small documentation fixes and cleanup