Changes in Version 1.1-0

  o Fixed diagonal matrix computations in gstslshet(). Due to incorrect
 trace computations, prior versions could lead to erroneous results.
 However, for the Boston data in Piras (2009) - see the vignette for more
 details - only slight differences occur.

Details:

The old command line
R> gammas<-as(Diagonal(,as.vector(gamma)),"sparseMatrix")
in the function gstslshet() was producing incorrect results in the computation of the following trace term (for R versions newer than 2.9.0):
R> tr1<-sum(diag(A1A1t%*%gammas%*%A1A1t%*%gammas))/2
For the Boston data results are only slightly different from those in Piras (2009) 
(see sphet vignette for greater details).
With different data, differences could be quite large. 


  o added the zero.policy option as in spdep
  
  o impacts() calculation for objects of class "sphet"


Changes in Version 1.2-0

  o Added the function spreg to match stata and GeoDa. 


Changes in Version 1.4-0

  o Read the instrument and endogenous variable from the data