Experimental ESXi Support

Added an experimental build ESXi MachineManager support.

Supports snapshots, power state, and networking.
status bug in esxi

status bug
Update modules/machinemanagers/vmware_esx.py
added enhanced behavior processing
Added processed state to database and scheduler
added failure state
Introduced auxiliary modules and refactored plugins system
Restored version check
Removed GrayLog support as nobody seems to be using it
Updated processing util
Updated CHANGELOG
Typos and style
Merge branch 'processed_state' of git://github.com/Thorsten-Sick/cuckoo into Thorsten-Sick-processed_state

Conflicts:
	docs/CHANGELOG
Merge branch 'development' of github.com:cuckoobox/cuckoo into development
Changed status logic
Added automated reschedule of locked tasks
Added API to reschedule tasks
Fixed typo
Added filter for category on list_tasks()
Added docstring