a more complete CPU info query

[guruofquality]

sigar win32 cpu info broken - use GetLogicalProcessorInformationEx

We need to drop sigar all together and make an abstraction for a general system processor (multicore/numa) query. Sigar is overkill for what we need, and its too buggy.

[guruofquality]

We probably need a better version of CPU info query that tells us:

• number of cpus
• numa nodes on the system
• cpus per numa node
• number of SMT cores
• cache sizes

https://github.com/pothosware/pothos-library/blob/master/include/Pothos/System/Info.hpp

[guruofquality]

Another relevant project: http://libcpuid.sourceforge.net/

• https://github.com/anrieff/libcpuid/blob/master/libcpuid/libcpuid.h#L121

[guruofquality]

Closing this off because inclusion of NUMA support: https://github.com/pothosware/pothos-library/issues/47

SIgar was also removed in the NUMA support branch: https://github.com/pothosware/pothos/commit/079ca40909d971b9fb9ad0c3820721e00d5dfe36

Will revisit other types of info to query when relevant.