Tor 0.2.4.19 now stable, devel now 0.2.5.1-alpha

As per announcements:

* https://lists.torproject.org/pipermail/tor-talk/2013-December/031392.html
* https://blog.torproject.org/blog/tor-weekly-news-%E2%80%94-december-18th-2013
* https://lists.torproject.org/pipermail/tor-talk/2013-October/030269.html