Implement several feature requests

[lbaca]

This pull request implements three feature requests:

• Feature request: remove the passed events #51 Hide finished events
• Feature request: sort events by starting time when displaying multiple calendars in event mode #39 Sort events by start time first rather than grouping by calendar
• Feature request: Show only the actual event #52 Show only currently running events
• feature request: max amount of events #37 Allow limiting total number of events

While I have tested these changes on my own setup, I am quite new to the whole process (LitElement, rollup, custom Lovelace cards, GitHub, working on forks, etc.). Therefore, please be aware that I may have taken some steps that may not be as you would usually expect them. Don't hesitate to correct me, as I wish to learn!

[vmcosco]

Thanks! How do these options implemented in the card config?

[lbaca]

Thanks! How do these options implemented in the card config?

I've updated the README.md to describe the two new options.

(BTW, do you know a better way to display a fragment of a file diff in a reply such as this one?)

[vmcosco]

(BTW, do you know a better way to display a fragment of a file diff in a reply such as this one?)

I do not. Sorry. Do you know when v0.90 will be pushed out to HACS?

[lbaca]

Do you know when v0.90 will be pushed out to HACS?

This is my first involvement with this project other than as a user, so I really don't know. It's up to @atomic7777.