Add extra parameters to `get_events()` method

[elliot-100]

At the moment there isn't a general-purpose method to get events.

e.g. getEvents can only get up to 100 events, and defaults to last 14 days; getEventsBetween can get more but requires date parameters. There is no way of restricting events to a Group.

I propose that get_events (PEP 8 naming as per #24) is expanded to:

• Default to a max, probably 100 for performance reasons, as getEventsBetween does now.
• Optional before/after datetime parameters, as getEventsBetween requires now (although I think the names could better reflect what they do)
• Optional Group ID filter parameter, as per #14
• Other optional parameters can then be added over time.

It might make sense to then have some supplementary 'shortcut' methods, but get_events_between may be redundant; I think it's too early to worry about backward compatibility.

I'm writing a PR for this, but any thoughts?

[Olen]

I totally agree.
It makes more sense to have a "generic" get_events with optional parameters, than different functions to basically do the same thing.

[elliot-100]

Pull request to implement this: #30

This does delete get_events_between(from_date, to_date), as it is functionally replaced by get_events(min_end, max_end).
Parameters are renamed (and added to) to better reflect the API parameters and what they actually do:

        max_end : datetime, optional
            Only include events which end before or at this datetime.
            Defaults to 100 for performance reasons.
            Uses `maxEndTimestamp` API parameter; relates to `endTimestamp` event attribute.
        max_start : datetime, optional
            Only include events which start before or at this datetime.
            Defaults to 100 for performance reasons.
            Uses `maxStartTimestamp` API parameter; relates to `startTimestamp` event attribute.
        min_end : datetime, optional
            Only include events which end after or at this datetime.
            Uses `minEndTimestamp` API parameter; relates to `endTimestamp` event attribute.
        min_start : datetime, optional
            Only include events which start after or at this datetime.
            Uses `minStartTimestamp` API parameter; relates to `startTimestamp` event attribute.

[elliot-100]

Thank you!