[Feature Request] Transform data from wide to long

[andreaphsz]

I think it would be very usefull to be able to select variables in a wide formated data frame that are then tranformed to the long format suitable for ggplot2. Thx

[GegznaV]

I think this feature would be great for the data pre-processing tool but it is out of the scope for data plotting tool. Of course, the authors of this package will do the final decision on this.