ENH: consistent output format for coupled geometry description (issue #278)

- In the corner case with few faces or points, the normal List I/O
  results in a compact list representation.

  This is less than desirable for external programs with simple
  line-based parsers.

- Write exactly the following

*Faces*
// Patch: <word-Region> <word-Patch>
<int-nFaces>
(
<int-faceSize>(<int> .. <int>)
...
)

*Points*
// Patch: <word-Region> <word-Patch>
<int-nPoints>
(
(<float-x> <float-y> <float-z>)
...
)

STYLE: only use serial form of createExternalCoupledPatchGeometry in tutorial

- less confusing for the user, who wonders why it is being done twice.