Large rework of the Linux backend: * there's no reason to read the whole topology info and temporarily   store in arrays of physical index when using sysfs, so move this   code to /proc/cpuinfo only * rewrite the whole sysfs code to generate objects on the fly
Large rework of the Linux backend:
* there's no reason to read the whole topology info and temporarily
  store in arrays of physical index when using sysfs, so move this
  code to /proc/cpuinfo only
* rewrite the whole sysfs code to generate objects on the fly

Consequences:
* we don't generate fake cache physical numbers anymore
* we don't ignore caches with broken shared_cpu_map anymore,
  we assume they are not shared
* we generate a die object even when there is a single die

The next step is to directly insert objects in the tree from the
backend and then assemble them into horizontal levels.

git-svn-id: 14be032f8f42541b1a281b51ae8ea69814daf20e@309 4b44e086-7f34-40ce-a3bd-00e031736276

BlueBrain/hwloc,BlueBrain/hwloc,BlueBrain/hwloc,BlueBrain/hwloc