- Test: does indexInInside for codim0-coupling always return 0?
- GridGlueVTKWriter doesn't seem to work
- GridGlueVTKWriter crashes when started on an empty GridGlue

For the upcoming paper:
./ remove target/domain naming
./ remove extractortraits
- rename Extractor to Patch
./ Extractor/Patch should get the predicate
./ remove remoteintersection(iterator)impl CRTP magic
(./) implement _new_ parallel merging (see article.tex)
./ move gridglue/adapter/gridglue.hh to gridglue/gridglue.hh
- add directed version communicate<FROM,TO, DH,DT>(data,iftype,dir)
   ... or similar
./ implement IndexSet

Interface changes:
- Merger gets (CoordType, dimG1, dimG2, dimworld, mergedDim) template parameters
- Merger::build(Range<CoordG1> verticesG1,
                Range<ExtractedEntityG1> entitiesG1,
                Range<CoordG2> verticesG2,
                Range<ExtractedEntityG2> entitiesG2)
- ExtractedEntity (name to be discussed) provides:
  * list of vertexIds
  * Dune::GeometryType
- Range describes begin and end iterator
