Changes in ssmrob version 1.0

	+ Documentation was updated. The current version accompanies the publication in the 
	Journal of Statistical Software, <doi:10.18637/jss.v099.i04> 
	
Changes in ssmrob version 0.8

	+ Data argument was added for functions ssmrob, heckitrob, heckit5rob and etregrob.

	+ The datasets were updated: binary variables are logical now. 
	Several variables with missing documentation were removed from MEPS2001 dataset. 
	Documentation for datasets was updated.

	+ Computation of the (co)variance matrix for the estimator was made more efficient.
	
	+ NAMESPACE was updated: instead of package namespaces (MASS, robustbase, sampleSelection)
	only the necessary functions are imported.
	
Changes in ssmrob version 0.7

	+ Generic functions nobs and model.matrix were added.
	
	+ print and summary outputs were adjusted to mimic more standard R model printing outputs.
	
	+ fitted model objects were extended, see documentation.

Changes in ssmrob version 0.6

    + Order of arguments in functions ssmrob, heckitrob, heckit5rob, etregrob was  
    changed. The selection formula is first, the outcome formula(s) is second.


Changes in robmed version 0.5

    + Number of digits after comma in print functions reduced to 4.
    
    + Chi-square probability for covariate weights is 0.95, it was 0.9.
    
    + Splitted weight calculation for design space is introduced (see Zhelonkin, 		
    Genton, Ronchetti 2016, p.814).
    
    + etregrob function is added, robust estimation for Endogenous Treatment Model.


