Changed DataTester to use a mapping file with a list of all of the source directories and the srcML data directories they map to.
Updated GetAccessModifier parser methods to better handle missing modifiers and protected internal.
Merge branch 'topic-data-incrementalupdate' of https://github.com/abb-iss/SrcML.NET into topic-data-incrementalupdate
Merge branch 'topic-data-incrementalupdate' into data-demo