15. core: Further cleanup for for end of command coordination

The following patch introduces more cleanup to the code -
Renaming the classes to proper names (based on "Command")
Changing variables, method names, and fields

http://www.ovirt.org/Features/AsyncTaskManagerChanges_3.3
Change-Id: Ibc3c628b58510e500b24065f5d20253d5d7fba82
Signed-off-by: Yair Zaslavsky <yzaslavs@redhat.com>