MINOR: config: Add the threads support in cpu-map directive

MINOR: config: Add the threads support in cpu-map directive

Now, it is possible to bind CPU at the thread level instead of the process level
by defining a thread set in "cpu-map" directives. Thus, its format is now:

  cpu-map [auto:]<process-set>[/<thread-set>] <cpu-set>...

where <process-set> and <thread-set> must follow the format:

  all | odd | even | number[-[number]]

Having a process range and a thread range in same time with the "auto:" prefix
is not supported. Only one range is supported, the other one must be a fixed
number. But it is allowed when there is no "auto:" prefix.

Because it is possible to define a mapping for a process and another for a
thread on this process, threads will be bound on the intersection of their
mapping and the one of the process on which they are attached. If the
intersection is null, no specific binding will be set for the threads.