ENH: improvements and bug fixes

* LabelConverter self-test fixed
* updated the code according to the change in CTK DICOM DB API
 (waitForImportFinished is now synchronous)
* updated SNOMED table to use "structure of" instead of "entire" code
 (contributed by David Clunie)
Merge pull request #186 from fedorov/update-Reporting

Reporting - improvements and bug fixes