Added new name helper functions for getting the last nested name element out of a name element and getting all of the nested name elements *except* the last one.

Moved the name helper functions to a new "NameHelper" static class.

Added tests for the NameHelper functions.
Merge branch 'topic-data-incrementalupdate' of github.com:abb-iss/SrcML.NET into topic-data-incrementalupdate