indicator is written by a mad man!

[antongrau]

lets just convert it to our friend xtabs!

[antongrau]

We need to make a new class for indicator() that retains the variables as attributes. This is not easy since R drops all attributes when subsetting matrixes. see ?Extract
See this thread for a possible solution with a new class:
https://stackoverflow.com/questions/9486342/subset-drops-attributes-on-vectors-how-to-maintain-persist-them