This file was duplicated from BOOST 1.64 because it appeared in a boost
release that was younger than the oldest boost release supported by CGAL
when the file was first required.
The minimum boost version (1.57) now required by CGAL is younger
than the version in which the file appeared in boost (1.51)
and it can thus be removed.
Assuming an EMST based on a regular triangulation makes sense, it should be
coherent in its distance: in the Delaunay version, we use the Euclidean
distance, so the power distance should be used for the regular triangulation
version.