Remove observation for each object during dealloc, check that block exists before execution.
Remove observation for each object during dealloc, check that block exists before execution.

ftiff/autopkgr,eahrold/autopkgr,HyppHere/autopkgr,HyppHere/autopkgr,HyppHere/autopkgr,lindegroup/autopkgr,eahrold/autopkgr,eahrold/autopkgr,lindegroup/autopkgr,lindegroup/autopkgr,lindegroup/autopkgr,ftiff/autopkgr,lindegroup/autopkgr,ftiff/autopkgr