add doxygen for yajr::Peer and yajr::Listener

Change-Id: I06de15fca9376fc4791c63892edaba5303fb38af
Signed-off-by: Alessandro Salvatori <sandr8@gmail.com>
distribute opflex/engine/internal/OpflexPool.h

Change-Id: Ib1a44d51aad714deff50906589344eb24f344484
Signed-off-by: Alessandro Salvatori <sandr8@gmail.com>