Updated data dictionary for DICOM 2013 edition.

Updated data dictionary for the latest edition of the DICOM standard, which
has been released on 2014-04-30. Major parts of the "dicom.dic" file have
been generated automatically based on the machine-readable DocBook version of
Part 6 and 7 of the DICOM standard. In addition, all recently approved final
text Supplements and CPs have been added manually. Since the data dictionary
was already quite up-to-date, there should be minor changes only.