This patch enhances the Capture::Connection::Screen such that the
bounding box of the affected pixels can be tracked by the caller,
which can use this information to adjust its behavior to the
activity/inactivity of the capture server.
Issue #5344
This patch adds the physical screen size as argument to the
Capture::Session::buffer RPC function, which allows drivers to
propagate DPI information to the GUI server. While changing the
the interface, the patch replaces the former use of C++ exceptions
by a result type. The 'Buffer_result' is handled transparently by the
Capture::Connection. The client.h code is now integrated in
connection.h.
Issue #5344
