If the `request` or `plugin` parameter that are injected by the
framework where before or inbetween positional arguments we'd be
injecting them incorrectly, i.e., we'd be providing them both as
`args` (and mismapping another argument) as well as `kwargs`.
This is a better way to map arguments, which takes advantage of the
fact that JSON-RPC calls are either all positional or named arguments.
I also included a test for various scenarios, that hopefull cover the
most common cases.
Reported-by: Rene Pickhardt <@renepickhardt>
Signed-off-by: Christian Decker <decker.christian@gmail.com>
