[Tracker] chm indexing

["seba fernandez" <sebastianfernandez6 gmail com>]

Hi, my name is seba. I have been using tracker for some time, it is
really good software.
But i would like to add chm support thought chmlib. I would like to
know if there is anything bad with this format. If not i will start
working in this and post the patch here.

Regards, Seba.

PS: Sorry if this has already been discussed.