* fix forwarding webxdc instances, add a test for that
* adapt webxdc test to fail on info-messages added when in draft mode
* do not add info-messages when in draft-mode
* half the number of instance-loads per webxdc update send/receive
the summary can be modified by the apps using
`sendUpdate({summary: "foo", payload: ...})`
the summary is updated when there is no newer update
and chat will be informed by the change as usual by
`DC_EVENT_MSGS_CHANGED`.
additional parameters will be `summary` and `msg` (for an info-message)
right now, and maybe more in the future (`aggregated`, `fast`, `to` ...),
so adding just more parameters easily gets wild.
also, this makes adaptions easier as no ffi needs to be adapted
when we add more parameters.
finally, sending is in-sync with receiving, database and wire now,
one receives similar objects as one sends,
which also looks like the right thing :)
for now, `sendUpdate()` also allows to use the old, unwrapped payload
to not immediately break existing `.xdc`, however, that will be removed soon,
probably before the first release.
