Update developer documentation
Update developer documentation

Tell users to pull docker-compose from Docker Inc.
Recommend rc3 or greater
Tell users the thread where the bump releases are being discussed
Fix typo in libvirtd

Change-Id: Ib47d3a57452a4266db2b47b41a789908365fda9b

dardelean/kolla-ansible,meticulo3366/kolla,LoHChina/kolla,rajalokan/kolla,mrangana/kolla,LoHChina/kolla,mrangana/kolla,rahulunair/kolla,mandre/kolla,intel-onp/kolla,fdumpling/kolla,brk3/kolla,negronjl/kolla,invenfantasy/kolla,intel-onp/kolla,rahulunair/kolla,openstack/kolla,negronjl/kolla,chenzhiwei/kolla,chenzhiwei/kolla,invenfantasy/kolla,HackToday/kolla,toby82/kolla,GalenMa/kolla,coolsvap/kolla,stackforge/kolla,fdumpling/kolla,rajalokan/kolla,coolsvap/kolla,coolsvap/kolla,jakedahn/kolla,chenzhiwei/kolla,tonyli71/kolla,HackToday/kolla,mandre/kolla,HackToday/kolla,LoHChina/kolla,dardelean/kolla-ansible,fdumpling/kolla,limamauricio/mykolla,toby82/kolla,rajalokan/kolla,limamauricio/mykolla,stackforge/kolla,meticulo3366/kolla,jakedahn/kolla,negronjl/kolla,invenfantasy/kolla,GalenMa/kolla,openstack/kolla,stackforge/kolla,jakedahn/kolla,tonyli71/kolla,brk3/kolla,limamauricio/mykolla,nihilifer/kolla,toby82/kolla,nihilifer/kolla,mandre/kolla,dardelean/kolla-ansible