Recurring events

[Taluu]

As it was written in #2, this is the continuation of the implementation of the recurring events parsing.

Should be based on the RFC 2445

• Parse RRULES correctly
  • create tokens based on http://www.kanzaki.com/docs/ical/recur.html
  • Interpret those tokens
  • Reflect a little bit more on the rules architecture
• Handle short cancelled recurred event (Google)
• Handle recurring events correctly (Google)