This patch prevents nitpicker from requesting a framebuffer and input
session by default because the regular use of nitpicker relies on the
capture-session and event-session interfaces by now.
For supporting the nested use of nitpicker via the gui_fb component, it
is still possible to enable the traditional behavior by explicitely
setting the 'request_input' and 'request_framebuffer' config attributes
to "yes".
Issue #3812