v2.17.0

• upgrade to Universal Dependencies version 2.17
• upgrade to alpino_ds.dtd version 1.17 (this 17 has no relation to the one above)
• library:
  • new function DtdVersion()
  • new function Release() returns software version
  • function VersionID() no longer returns an updated number when the software is updated, unless the results of the parser have changed
• commands:
  • bugfix for option -c
• other:
  • code clean-up