Event linking improvements

[rdallecoexya]

The dependencies between events works well with the word "after" and "before". But it lacks some other situations, and i think the following words could be very useful :

• starts with !eventID
• ends with !eventID
• starts [duration] after !eventID
• ends [duration] before !eventID

And the best would be to be able to combine two of them, for example : an event A has to start with an another event (B), and ends with an event (B) or (C). and then the duration of event A is strictly relative to others

Hope this suggestion will find a positive decision.
Thank you very much for this awesome tool.

Regards
Romain