Changes for R-package tempdisagg

Version 0.21 (Jan 21th, 2013)
  Changes visible to the user:
  - new methods available: "chow-lin-fixed" and "litterman-fixed". 
    Using the "fixed.rho" argument, an autoregressive parameter may be specified
    by the user.
  - interface changes: "chow-lin-maxlog-ecotrim" and "chow-lin-maxlog-quilis"
    are defined as new methods. No need for the old 'vcov' argument anymore.
  - new defaults: method = "chow-lin-maxlog", neg.rho = FALSE
    with positive values for rho only, the chow-lin-maxlog method generally 
    outperforms the other methods.
  - all relevant arguments are directly entered to td()
  - summary output: If neg.rho = FALSE and a negative rho is truncated to 0, and 
    indicator is shown in the summary output.
  - non time-series mode: optionally, standard vectors can be used instead of time 
    series. In this case, the frequency of low frequency variable is 1, while
    the fraction of the high frequency variable is specified by the 'to'
    argument
  - updated help files

  Invisible changes:
  - td() is rewritten and has a clear structure now.
  - GLS Regressions are performed by the new CalcGLS() function, which uses 
    QR-decomposition instead of matrix-inversion. This is faster and 
    numerically stable. It resolves an issue wher large (or small) numbers have
    led to a 'system is computationally singular' error.

