Guard PIConnection, thread primitives, PICodeParser and other feature
code behind PIP_HAS_THREADS/PIP_HAS_FILESYSTEM. In CMake generate the
feature flags summary from the single PIP_HAS_FLAGS list (used by the
add_definitions loop as well), default ICU to OFF and make introspection
also require PIP_HAS_SOCKET. Build system/thread test suites only when
the corresponding feature flags are enabled.
PIThread::stopAndWait now returns bool
PIKbdListener on Linux now use piwaitevent_p and can immediately stop
new base method piZeroMemory, also migrate all "memset 0" to piZeroMemory
apply some code analyzer recommendations
ICU flag now check if libicu exists
prepare for more accurate growth of containers (limited PoT, then constantly increase size)
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