nrrd input support for embedded remeshing

[daniel-zint]

For the embedded remeshing component, we need to read the output data from 3d-slicer. Thus, I will add the teem library which contains the original nrrd read/write code.

• create structure for embedded_remeshing component similar to adaptive_tessellation so that it can hold its own dependencies
• add nrrd as dependency
• load nrrd file
• construct mesh from nrrd file with tags according to the segmentation