Extend cpupools to support numa

Extend cpupools to support numa

The user interfaces for cpupools are extended to support numa machines:
- xl cpupool-create supports now specifying a node list instead of a cpu list.
  The new cpupool will be created with all free cpus of the specified numa
  nodes.
- xl cpupool-cpu-remove and xl cpupool-cpu-add can take a node number instead
  of a cpu number. Using 'node:1' for the cpu parameter will, depending on
  the operation, either remove all cpus of node 1 in the specified cpupool,
  or add all free cpus of node 1 to the cpupool.

libxl is extended with the following functions to support this feature:
int libxl_cpupool_cpuadd_node(libxl_ctx *ctx, uint32_t poolid, int node, int *cpus)
int libxl_cpupool_cpuremove_node(libxl_ctx *ctx, uint32_t poolid, int node, int *cpus)

Signed-off-by: juergen.gross@ts.fujitsu.com
Signed-off-by: Ian Jackson <ian.jackson.citrix.com>