Import calendar

@anthonywebb,

These are changes to the calendar and weather modules as a result of my memory leak crisis.

I am sure some changes will make you laugh, but I have kind of become paranoid: I see leaks everywhere now. The scope model of JavaScript has surprising effects, so I take no chance.

I also added loading a calendar from file, with the intend of using this to compare memory use with http/https. I found the GC options (found while looking for tracing GC activity) before I could compare. Oh well.. It might be convenient to someone with a file server and non-Google or non-Web calendar. It was trivial anyway.

I have not touched server.js, but we might have a bit too many setInterval there (I have become paranoid for real :-).