src/

- copy constructur and assignment for class intset and timer
- method transp(), inv() for class mat
- method neg() for class vec and mat meaning vEQMIv mEQMIm
- implement EXP macro from Neural Computation Article (2/1999) as a compiler switch
  as an alternative to standard exp() function. Also for tanh(). 

R/

- hessian.ffnet () for time series 
- implement simulate.ffnet () for regression and time series
- predict.ffnet.formula(), hessian.ffnet.formula(), therefore ffnet.formula()
  returns an object of class(nn) <- c("ffnet.formula", "ffnet")

