Update links on slashie webpage

Hi slashie, please update links on your main website to point to the github repo.
https://slashie.net/libjcsi/

(Also, playbandersnatch seems broken. I have a bit of time at the moment, if you want any help setting up hosting for your stuff, I might be able to do some sysadmin for you. Feel free to get in touch on channel rgrd)
