add serialization/pijsonserialization.h for JSON de/serialization
add -J flag for pip_cmg to make JSON serialization methods
not finished yet, but basically workable now
in almost all methods removed timeouts in milliseconds, replaced to PISystemTime
PITimer rewrite, remove internal impl, now only thread implementation, API similar to PIThread
PITimer API no longer pass void*
PIPeer, PIConnection improved stability on reinit and exit
PISystemTime new methods
pisd now exit without hanging
