In DESCRIPTION: Added "forecast" to Suggests because the package is
needed for a complete build of the timeseries vignette.

In vignettes:
* Fixed some typos
* Did some formatting
  - added spaces
  - inserted \code where missing
  - wrapped some long code lines
  - added second # to comment lines (Emacs likes that)
* The timeseries vignette can now be built without the "forecast"
  package. If the package is missing, the following note is shown in
  the document instead of the auto.arima() example: An example was
  dropped because "forecast" is not available.
* Moved around various sections of the timeseries vignette around the
  auto.arima() example. This was done to facilitate the conditional
  inclusion of the example: it is easier to exclude one big chunk of
  an example than have the conditional text and figure intertwined
  with contents that are always included.


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/dplr@833 edb9625f-4e0d-4859-8d74-9fd3b1da38cb