Until now, the implementation of the overrides in `SelectionBlueprint`
have been confusing to the point where I would just implement by
trial-and-error (or copying from an existing implementation). This was
due to a combination of using "object" space coordinates
(ie. the thing the `Blueprint` is operating on) and screen-space coordinates.
This change switches all event related coordinates to screen-space,
which is how we already handle rotation/scale operations. With the
introduction of other editor types where the related objects are
drawables, this also makes a lot more sense.
Override SetLifetimeStart/SetLifetimeEnd separately to track individual assignment. It is necessary to ensure real lifetime is not lost when lifetime is partially updated.
Hidden properties are used when the type is the base class. It caused issues when `DrawableHitObject` logic is factored out to `PoolableDrawableWithLifetime` because it is using the base `LifetimeEntry`, not `HitObjectLifetimeEntry`.
Added these in a previous iteration, where I had the mania variant inherit this class.
No longer necessary as `IHasColumn` was used to make this check more generic.
Will potentially have `CheckUnsnappedKiai` or similar later, so this is worth specifying.
Also consistent with `CheckConcurrentObjects`, which will likely have a `CheckConcurrentLines` later.
Here we use `IHasColumn` to support rulesets with columns, and so I moved that interface out into `osu.Game` from `osu.Game.Rulesets.Mania`.
We also use the same threshold as the unsnap check to ensure that no problems slip through. Specifically where an object is simultaneously not concurrent and not unsnapped but still on the same tick.
Further separates them from `IBeatSnapProvider`'s `SnapTime`, and groups them together more, to prevent confusion between the two interfaces.
Also changes the xmldoc of the reference time to that of `IBeatSnapProvider` for consistency.
