split slab rebalance and automove threads
split slab rebalance and automove threads

slab rebalancer now chillaxes on a signal and waits a lot less time when
hitting a busy item. automove is its own thread now, and signals rebal when
necessary.

when entering the command "slabs reassign 1 2" it should start moving a
page instantly.

mitliucak/memcached,neutronsharc/memcached,allen8807/memcached-1,kamyu104/memcached,fengshao0907/memcached,bpzhang/memcached,msg7086/repcached,allen8807/memcached-1,neutronsharc/memcached,Dhruva6/memcached,memcached/memcached,xiaosl/memcached,xiaosl/memcached,13693100472/memcached,gencer/memcached,emcconville/memcached,elfchief/memcached,ZhangZhenhua/memcached,romanticode/memcached,tellapart/memcached,memcached/memcached,memcached/memcached,elfchief/memcached,elfchief/memcached,niaomingjian/memcached,surajdharmapuram/memcached,memcached/memcached,samt42/memcached,myPublicGit/memcached,leverich/memcached-affinity,xiaosl/memcached,mitliucak/memcached,elfchief/memcached,xiaosl/memcached,EdwardLee03/memcached,jbergstroem/memcached,williamcheungthu/memcached,rhli/memcached,msg7086/repcached,dianerdianer/memcached,dkrotx/memcached-dd,sagark/memcached-accel,dkrotx/memcached-dd,kamyu104/memcached,jeremiahyan/memcached,jeremiahyan/memcached,DSrcl/memcached,myPublicGit/memcached,fengshao0907/memcached,romanticode/memcached,zaycev/memcached,niaomingjian/memcached,emcconville/memcached,ClearwaterCore/memcached,myPublicGit/memcached,cloudrain21/memcached,tmharrisonwang/memcached,emcconville/memcached,guikcd/memcached,fengshao0907/memcached,EdwardLee03/memcached,rmccullagh/memcached,alexandermerritt/memcached,leverich/memcached-affinity,rmccullagh/memcached,memcached/memcached,ClearwaterCore/memcached,samanbarghi/memcached,dormando/memcached,romanticode/memcached,amyvmiwei/memcached,13693100472/memcached,mitliucak/memcached,Dhruva6/memcached,romanticode/memcached,ZhangZhenhua/memcached,alexandermerritt/memcached,sagark/memcached-accel,Distrotech/memcached,ZhangZhenhua/memcached,dianerdianer/memcached,guikcd/memcached,tomykaira/memcached,tomykaira/memcached,tmharrisonwang/memcached,kamyu104/memcached,13693100472/memcached,tellapart/memcached,msg7086/repcached,msg7086/repcached,ZhangZhenhua/memcached,niaomingjian/memcached,allen8807/memcached-1,Dhruva6/memcached,alexandermerritt/memcached,jeremiahyan/memcached,samt42/memcached,EdwardLee03/memcached,cloudrain21/memcached,williamcheungthu/memcached,amyvmiwei/memcached,rmccullagh/memcached,myPublicGit/memcached,rhli/memcached,gencer/memcached,sagark/memcached-accel,williamcheungthu/memcached,Dhruva6/memcached,surajdharmapuram/memcached,DigitalAce/memcached,guikcd/memcached,surajdharmapuram/memcached,tmharrisonwang/memcached,fengshao0907/memcached,cloudrain21/memcached,neutronsharc/memcached,mitliucak/memcached,niaomingjian/memcached,gencer/memcached,jeremiahyan/memcached,Distrotech/memcached,emcconville/memcached,tomykaira/memcached,leedc/memcached,allen8807/memcached-1,elfchief/memcached,leverich/memcached-affinity,amyvmiwei/memcached,dianerdianer/memcached,dkrotx/memcached-dd,DSrcl/memcached,rhli/memcached,samanbarghi/memcached,dkrotx/memcached-dd,DigitalAce/memcached,alexandermerritt/memcached,rmccullagh/memcached,Distrotech/memcached,guikcd/memcached,guikcd/memcached,sagark/memcached-accel,tomykaira/memcached,angusfenying/memcached-win64,leedc/memcached,dormando/memcached,samanbarghi/memcached,ClearwaterCore/memcached,leedc/memcached,bpzhang/memcached,ClearwaterCore/memcached,dormando/memcached,zaycev/memcached,angusfenying/memcached-win64,williamcheungthu/memcached,EdwardLee03/memcached,zaycev/memcached,jbergstroem/memcached,DSrcl/memcached,rhli/memcached,tellapart/memcached,bpzhang/memcached,Danzeer/memcached,gencer/memcached,angusfenying/memcached-win64,cloudrain21/memcached,Danzeer/memcached,dianerdianer/memcached,leedc/memcached,kamyu104/memcached,samt42/memcached,13693100472/memcached,DigitalAce/memcached,angusfenying/memcached-win64,tmharrisonwang/memcached,bpzhang/memcached,Danzeer/memcached,samanbarghi/memcached,gencer/memcached,jbergstroem/memcached,zaycev/memcached,dormando/memcached,surajdharmapuram/memcached,dormando/memcached,sagark/memcached-accel,msg7086/repcached,neutronsharc/memcached,13693100472/memcached,Danzeer/memcached,DSrcl/memcached,amyvmiwei/memcached,rmccullagh/memcached,samt42/memcached