I grepped for unencrypted links in the guidelines and went through and fixed them all up. In some cases there were hostname changes or redirects that caused issues which I could resolve by just using the proper host so I went ahead and did that.

A few plain http links do remain. Those are either to hosts that do not actually support encryption (Sourceforge, the Sugar wiki) or for links which are dead (ocaml-programming.de, the TCL/Tk wiki). I didn't worry about the former, and for the latter we should try to find replacement links. There are probably several other bad links in there so I guess running a link checker wouldn't be a bad idea.

I've done one commit per document. I can squash if that's an issue.

Edit: I did this because while cleaning out my inbox I found a three-year-old message asking me to fix http links in the NodeJS guidelines. Figured I would just clean up everything.