With this patch, the thread context area RM session gets created at
program startup to have the thread context area's virtual address range
reserved right from the beginning.
Fixes#734.
This patch implies that all Genode processes try to create an RM
session. So a route to the RM service must be present even for processes
that have only a single thread. Hence, the patch contains an update of
affected components.
With this change, init becomes able to respond to config changes by
restarting the scenario with the new config. To make this feature useful
in practice, init must not fail under any circumstances. Even on
conditions that were considered as fatal previously and led to the abort
of init (such as ambiguous names of the children or misconfiguration in
general), init must stay alive and responsive to config changes.
