Timezone Support & Several Other Fixes

[liebeskind]

Adds support for timezones so will set time properly. Also included several other fixes that were previously mentioned to make setting time in calendar invite function properly.

[nwcell]

There have been a ton of changes recently and this no longer merges properly. If the merge is fixed, I'll be happy to merge this in.

[asr1]

This pull request can be accepted instead of #43; this fixes that issue. I don't think it's possible to add this functionality without merge conflicts; the few breaking changes are necessary and also improvements wrt to time zone updates.

[nwcell]

If someone gets this merge-able, I'll merge it. It'll probably require a pull from origin... Or even a re-application of changes from the current master.

[asr1]

I attempted--I did a pull of the most recent and applied these changes and got the same results.
I believe this file (independently) incorporates the changes that were made during the merges last week (the big one being the change from getMinutes() to getSeconds().
Obviously this PR should be tested, but I believe the way to merge these changes to is take this file over the existing ics.js file.

[nwcell]

Yeah, the last commit to that repo was in 2015 (honestly, I forgot I made this project). It either needs to be updated with more current code, or the timezone stuff needs to be re-implemented in a fresh branch.

[asr1]

1. Let me just say--thank you for making this, it made my life much easier in developing a tool that in turn sped up routine tasks for more than 200 people.
2. What of this isn't compatible? It seems to be just changing the start date from new Date() to the new Date() with timezone offsets , and the changingn DATE to DATE-TIME at the end. This shouldn't affect the RRULE stuff that was added from Connorbode's branch.
   Am I missing something?

[michael-maltsev]

This calculation can be incorrect due to Daylight Saving Time (DST)