Sonador IO Slicer plugin

Slicer plugin to provide support for import of data from Sonador to 3D Slicer.

• "Search Sonador" extension. Provides a search/import dialog that can be used to import data to the local Slicer 3D database.
• "DICOMM3D" plugin. Extension which provides support for import 3D models to a Slicer scene.
• Create an export plugin that allow for 3D models to be exported to DICOM.
  • Allow for multiple models to be exported to a single series by nesting child models under a top-level model. The Slicer hierarchy features allow for this, though it may not be a deliberate feature. Grouping models under a folder does not work because it does not expose an "Export to DICOM" feature. The proposed workaround is not a workable solution. Attempting to nest models results in error messages from Sonador.
• Add "export to Sonador" button to the plugin so that it is possible to send data to an Orthanc instance