Fix missing array include in kmeansclusteringdialog.cpp
Fix missing array include in kmeansclusteringdialog.cpp

This fixes a missing include for <boost/array.hpp> in the
kmeansclusteringdialog.cpp file.

Change-Id: I4a68d51a5f8821139268b933bd8f6048d671ada6

OpenChemistry/mongochem,OpenChemistry/mongochem,OpenChemistry/mongochem