dlsem (2.4)

* fixed the bug in lagPlot() for gamma lag shapes
* fixed the bug in causalEff() for multiple starting variables
* methods lagPlot() and causalEff() now return NULL instead of an error in case of inexisting path
* lag shape transformations are visible to the user
* added the minimum gestation lag option in dlsem()
* added the gestation and the lead lags in the summary
* added the 'npar' method for class 'dlsem'
* added the vcovHAC() method for class 'lm' and 'dlsem'
* added the HAC estimate of standard errors in method dlsem()


dlsem (2.4.1)

* fixed the bug in the visualization of the cumulative coefficient in lagPlot()
* changed the call to the gamma lag transformation from gamma.lag() into gamm.lag()
* gamm.lag() is visible to the user


dlsem (2.4.2)

* added the deseasonalization procedure into dlsem()
* the imputation procedure into dlsem() is now performed before differentiation and takes into
  account of the relevant autoregressive terms
* changed the algorithm for the adaptation of gamma lag shapes:
  now a grid search on several pairs of delta and lambda is performed, ignoring the constraints
  on the lag length and considering a number of time lags equal to 2/3 the sample size
* added the option 'gammaOptim' into dlsem() to speed up the adaptation of gamma lag shapes