Make message_oriented_connection clean up its async tasks on destruction
Make message_oriented_connection clean up its async tasks on destruction

bitshares/bitshares,dacsunlimited/dac_play,camponez/bitshares,bitsuperlab/cpp-play,FollowMyVote/bitshares,bitshares/bitshares,bitsuperlab/cpp-play,bitshares/bitshares-0.x,camponez/bitshares,Ziftr/bitshares,jakeporter/Bitshares,RemitaBit/Remitabit,bitshares/bitshares,camponez/bitshares,RemitaBit/Remitabit,jakeporter/Bitshares,bitshares/bitshares,dacsunlimited/dac_play,RemitaBit/Remitabit,jakeporter/Bitshares,FollowMyVote/bitshares,FollowMyVote/bitshares,jakeporter/Bitshares,frrp/bitshares,denkhaus/bitsharesx,frrp/bitshares,bitshares/bitshares-0.x,RemitaBit/Remitabit,FollowMyVote/bitshares,jakeporter/Bitshares,bitshares/bitshares,bitshares/bitshares-0.x,jakeporter/Bitshares,bitsuperlab/cpp-play,frrp/bitshares,bitshares/devshares,bitsuperlab/cpp-play,bitshares/devshares,dacsunlimited/dac_play,drltc/keyid,frrp/bitshares,drltc/keyid,camponez/bitshares,Ziftr/bitshares,dacsunlimited/dac_play,bitshares/bitshares-0.x,dacsunlimited/dac_play,bitshares/bitshares,RemitaBit/Remitabit,FollowMyVote/bitshares,bitshares/devshares,Ziftr/bitshares,camponez/bitshares,bitsuperlab/cpp-play,drltc/keyid,RemitaBit/Remitabit,drltc/keyid,bitshares/devshares,frrp/bitshares,denkhaus/bitsharesx,camponez/bitshares,dacsunlimited/dac_play,bitshares/devshares,Ziftr/bitshares,bitshares/devshares,denkhaus/bitsharesx,bitshares/bitshares-0.x,FollowMyVote/bitshares,frrp/bitshares,bitshares/bitshares-0.x,denkhaus/bitsharesx,bitsuperlab/cpp-play