Remove the `obsolete` directory?

[wtbarnes]

If these routines are not meant to be used and/or don't work, we should avoid distributing them with the code. Their existence will still persist in the history of the git repository.

[pryoung]

These routines all still work I believe, but have been superceded by other routines or lack some of the more recent functionality. Anyways we shouldn't be distributing them, so I now flag the obsolete folder so that it doesn't get included in the IDL tar file when I create a new version of CHIANTI software. One concern was that these routines may still be called in the recesses of some of the other routines, thus they may lead to a crash if they're removed. Also some users may still be using these routines in their own code. I think if we can survive a couple of releases without complaints then we can delete the folder.