This still leaves out setting a client to online/offline, since that
seems to be causing the CPU issues with synapse.

It currently causes severe performance issues in synapse as well as many
random resets, so this is disabled until those issues are resolved.

Fixes some issues with inline images.

fixes #214

Limiting improves readability on wide monitors.

The immediate update of the settings is done by just exposing settings
as properties and then setting the settings as a context property.

Messages on /sync don't have a room_id

(This is such a hack and will probably break, but it works for now for
most cases...)

This is necessary to support having a picker within QML.
Eventually, this should replace the existing widget-based one.