Use rfc2445 for scheduling definitions

[ligi]

https://tools.ietf.org/html/rfc2445

nice hint from @dschuermann at 33c3

[dschuermann]

@ligi I think this is the current version: https://tools.ietf.org/html/rfc5545#section-3.8.5.3

[ligi]

thanks for the follow-up! Did not dig deep into this yesterday - this here was mainly that I do not forget about it..

[ligi]

@johnjohndoe what is the standard the wo-ist-markt project uses for this problem? You had this as an example in your talk at 33c3 when I remember correctly - also had the feeling this was more readable - any drabacks?

[johnjohndoe]

wo-ist-markt refers to the OpenStreetMap opening hours format specification with regards to opening hours for the markets (including repetetive events).