Changes in simPopulation version 0.1.1

    + Argument 'const' added to functions 'simContinuous' and 'simEUSILC' so 
      that constant can be added before log transformation.
    
    + Bugfix in 'getCat': it produced an error for semi-continuous variables 
      when there were either no negative or no positive breakpoints.
    
    + Added help file for package.