setup.py: Update url

[jayvdb]

http://trevp.net/ shows Under construction

[tomato42]

this repository is dead, I have an active fork at https://github.com/tomato42/tlslite-ng

[jayvdb]

@tomato42 ya , but the metadata here and on https://pypi.org/project/tlslite/ has a dead link.
It would be nice if that could be fixed here at least, and ideally a new patch release emits new metadata and even has a description which informs people that it is no longer being maintained and suggests they use tlslite-ng instead.

[tomato42]

by definition, dead means no changes will happen in it