fixing indent in Cloubed.gen_file()
raise CloubedException if template not found
add new memory size parser

The memory size defined in Cloubed YAML file for a domain now accepts optional
units such as GB, M or MiB. Default if no unit is still GiB but Cloubed now
manipulates MiB internally instead.
raise CloubedException if template write error

CloubedException is now raised if the template output file could not be
written. This may be because the output directory does not exist for example.
test libvirt still defined in loop of EventManager

(see added comment in diff for all useful details.)
complete README with dependencies for Spice