This patch moves the thread iterator function declarations in GDB
monitor's 'Cpu_session_component' above the 'CPU session interface'
comment, because these functions are not part of the CPU session
interface anymore.
Fixes#10.
This patch introduces the functions 'affinity' and 'num_cpus' to the CPU
session interface. The interface extension will allow the assignment of
individual threads to CPUs. At this point, it is just a stub with no
actual platform support.