Fix crash on SIGHUP signal when system is being unregistered
Fix incompatibility with python 2.4
libvirt domain instance might not have state method
Restructure the code

Many improvements in the code structure, some highlights:
* All the virt backend are inherited from base class
* All the subscription managers are inherited from base class
* Modules moved to subdirectories
* Ability to use configuration files
* Use daemon library for daemonization
*
Add tests for common functionality
Add ability to encrypt passwords
Version 0.10
virt: add missing import to hyperv
libvirtd: remove import to nonexistent file
conf: add remark about quoting special characters
Add missing license header
Use libvirtd as fallback when no configrations are found

This is needed in order to maintain compatibility with older releases of
virt-who.
fix password test

Mock checking if it run as root
libvirtd: use event loop instead of reconnecting all the time
Fix hypervisorCheckIn API and add test for it
Fix wrong logger usage when processing update errors
test: fix hypervisorCheckIn function parameters
libvirt: properly handle libvirt shutdown when doing background monitoring
libvirtd: use info() when state() is not implemented

state() method is not implemented on older libvirt, use first value from
info() instead.
esx: disable error when esx host doesn't have guests

It works fine in this case, no need to show an error.