[dxwg] new commits pushed by davebrowning

The following commits were just pushed by davebrowning to https://github.com/w3c/dxwg:

* Minor clean-up
  by Simon Cox
https://github.com/w3c/dxwg/commit/7b7bbb815f27036d189317b463ea20980a8ab91b

* Some fixes to the dcat-sdo mapping
  by Alejandra Gonzalez-Beltran
https://github.com/w3c/dxwg/commit/c3ccc3d5299d509ef50b9fdaea3d566480be2b8b

* Merge pull request #421 from w3c/dcat-ed-nits-simon

Minor clean-up
  by David Browning
https://github.com/w3c/dxwg/commit/08dc09091911414254abc61e06acc286b13474a8