Fixed as per solution at https://github.com/JamesNK/Newtonsoft.Json/issues/874.
Note that due to the use of `JsonExtensionDataAttribute` it's not
feasible to change the actual specification to `JValue` in the
`Dictionary`.
In discussion with the osu-web team, it may be worthwhile to change the cursor
to a string format where parsing is not required at our end. We could already
do this in fact, but there are tests that rely on it being a `JToken` so the
switch to `JValue` seems like the easier path right now.
There are seemingly no C#-side compile-time guarantees that it is safe,
but if the task's state is `Faulted` (as is checked right before), the
exception cannot be null as per the documentation.
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.