Merge branch 'feature/nekmesh-check-links' into 'master'
Feature/nekmesh-check-links Clears the existing element links in the mesh and reprocesses them. It then checks that all faces are linked to two elements or to one element and a boundary face. Designed to be used with the bl split module to detect errors and user mistakes (creating hanging faces etc). Its been made into its own module so it can be used anywhere. See merge request !691