Issues/50 from ical, cleaned up

Cleanup of #226.

Squashed all commits into one, removed non-ical changes, unbroke tests, and committed. Sorry to have lost all the contributors, but it was too unwieldy to rebase. Credits to @skyporter @jgauby @btucker @spra85.

I hope this helps in getting iCal parsing finally merged.
Ah thanks. I'm using Rails 4.1.6, which behaves differently:
```
[1] pry(main)> DateTime.now
=> Wed, 19 Nov 2014 22:05:32 +0100
[2] pry(main)> DateTime.now.class
=> DateTime
[3] pry(main)> DateTime.now.to_time.class
=> Time
[4] pry(main)> DateTime.now.utc.to_time.class
=> Time
[5] pry(main)> show-method DateTime.now.to_time
Error: Cannot locate this method: to_time.
```

I'm a bit at loss what to do now. It would be nice to know if the code functions incorrectly because of this - in that case I'd like to add a rails version conditional. If it's just a warning, I'd be inclined to leave it as it is.

And, thanks for your input - I'm not knowledgeable of everything, but perhaps together we cover the base :)