Now a binary is required which might not always be present, nor is
it created as pre-requisite of the test.
Until that is the case, say how this can be fixed.
Previously, the attempt was made to enable only those `tokio` features
that are actually used. However, due to default-features still being
enabled and `tauri` using the `full` feature, for most intents and purposes
that wasn't effective.
Now default features are disabled, and `full` isn't used anymore, forcing
all crates to mention the exact features they need.
Note that `tracing` is missing here, as it wasn't effective previously
without the `--cfg tokio_unstable` option also being specified as rustflag.
There are no doctests and it's unlikely there will be anytime soon
as this library isn't for publishing.
The binaries did try to build unit-tests as well even though these
aren't quite feasible, so they are disabled now to reduce clutter.
