netinfo-ffi 0.3.0

C FFI for netinfo, which groups network usage by process
Documentation
Fix full cpu usage

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Rename long NetStatistics::* to shorter version
Netinfo::stop_async()
ConnectionType to InoutType
Export Pid?
Newtype for NetworkInterface and MacAddr
Netifno::get_async_thread_state()

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OK see TODO
OK multiple network interfaces
WARN thread poisioning?
OK README.md
OK move *.c into examples/