A new binning type based on gain ratio

[lucazav]

It'd be great if the binning() function had a type of binning based on gain ration maximization.
Here an example of the discretize_rgr() function implemented into the funModeling package.

[choonghyunryu]

@lucazav
Thanks for the great feature suggestion.
I will add the features you suggested to the next version.

[choonghyunryu]

@lucazav,

To submit to CRAN, the number of imported packages must be less than 20. By the way, the binning you suggested is to add the import package. This makes it difficult to keep packages on CRAN. So I put off development.

However, I implemented the function today by putting that package, funModeling, as 'Suggests' rather than 'Imports'.

Sorry for the very late appointment.

The name of the function is binning_rgr().

[choonghyunryu]

I close the issue because I implemented that function.