- some central (core) bits under fileFormats,

- general surface reading relocated from sampling to surfMesh since it
  does not use any sampling-specific components and will permit
  re-use in meshTools (for example)

- remove old mask, subDir methods from ensightFile which were
  previously relocated to ensightCase

- improve handling of 'undef' values when generating and reading,
  respect Ensight component ordering when reading.