o Split R source in thematical parts --
  according to the sections in Chapter 12 of the book.

 File		   Section  Title					Pages
 ----		   -------  -----					-----
 R/simFracGauss.R  12.1.1   Simulation of fractional Gaussian noise	218-220
 R/simFracARIMA.R  12.1.2   Simulation of fractional ARIMA($0,d,0$)	220-223
 R/WhittleEst.R	   12.1.3   Whittle estimator for fractional Gaussian
			            noise and fractional ARIMA(p,d,q)	223-233
 R/polyFEXP.R	   12.1.4   Approximate MLE for polynomial FEXP-models	233-237


o I decided to try to make the two spectrum() functions compatible to the
  standard  spectrum() and spec.ar() functions
  ==> name change from 'fspec*' to 'spec*'

o The 2 original ``main programs''  have become new functions :

  R/polyFEXP.R	  FEXPest()
  R/WhittleEst.R  fARIMA()

