Pylint fixes

This is some attempts to lower the number of pylint warnings. I've taken some shortcuts in doing so; e.g the HDS fetcher had a lot of unused variables. I didn't want to remove them, as they seem to be useful in "documenting" how HDS works, but I did comment them out.

The pylint warnings aren't gone completely, but they are getting fewer and fewer.

Current "rating" on my machine:

    Your code has been rated at 9.64/10