Full Timezone support when parsing ical

[seejohnrun]

This PR builds on the great work from #335 (thanks @dcosson)

I'll be removing the need for ActiveSupport here.

Also, added support for parsing RDATE while I'm in here.

Closes #335

[seejohnrun]

@avit do you think we should move ical parsing out of ice_cube proper as part of this? Then we could avoid having to wrap with active_support conditionals.

[avit]

I like the idea... are you thinking of a separate gem, or maybe just an optional require?

[seejohnrun]

I think the optional require makes sense, but separate gem also sounds like a decent idea to me. I just dislike that we're potentially having two different behaviors in the ical parser dependending if AS is loaded or not

[avit]

We have a dependency on ActiveSupport here. Maybe this can work with TimeUtil.deserialize_time by passing a hash to it.

[seejohnrun]

@avit Ah I like that idea - will update this soon

[dcosson]

Any update on this?

It's really a bummer that this has been roadblocked for years at this point, even though the current behavior which is completely broken w.r.t. daylight savings time, just to avoid the dependency on ActiveSupport. With all due respect, what's more important - having a library that works and solves people's problems, or keeping the dependencies down?

[seejohnrun]

What do people think of the compromise of just making this method raise if ActiveSupport hasn't been required and we're attempting to parse a time with zone? I'm not 100% against the idea of the added dependency anymore, but want to make sure we're doing it for a reason that is required. I'm sorry this has held you up @dcosson and hopefully this branch has been useful to you.

[dcosson]

No worries, thanks for your continuing work maintaining this library. Hopefully it's close now!

+1 from me on raising if ActiveSupport isn't available.

[jorroll]

Seems like a good idea.