added citygml-tools link

docs/software.rst

@@ -16,7 +16,9 @@ Software supporting CityJSON
 ----------------------------
 
   - `cjio <https://github.com/tudelft3d/cjio>`_: Python CLI to process and manipulate CityJSON files. The different operators can be chained to perform several processing operations in one step, the CityJSON model goes through them and different versions of the CityJSON model can be saved as files along the pipeline. Also used as the 'official validator' for CityJSON files.
-  - `citygml4j <https://github.com/citygml4j/citygml4j>`_: The open-source Java API for CityGML, allows us to convert back and forth between CityJSON and CityGML
+  - `citygml4j <https://github.com/citygml4j/citygml4j>`_: The open-source Java API for CityGML,
+  - `citygml-tools <https://github.com/citygml4j/citygml-tools>`_: CLI created with citygml4j, it
+   allows us to convert  CityJSON <-> CityGML in one-click. It's great!
   - `3dfier <https://github.com/tudelft3d/3dfier>`_: '3dfication' of 2D GIS datasets
   - `azul <https://github.com/tudelft3d/azul>`_: 3D city model viewer for Mac; full support for v0.5+ (including Extensions), except of the textures/materials
   - `val3dity <https://github.com/tudelft3d/val3dity>`_: validation of the geometric 3D primitives (everything is supported in master branch); the `web-application <http://geovalidation.bk.tudelft.nl/val3dity/>`_ also fully CityJSON input