Fixed GetLogs request error management.
Changed Notifications API call to the latest format.
Fixes cesaraugustogarcia/cloudhub-client-py#8 tenants not being paginated.
Added customizable output format for Notifications.
Updated commands arguments.
Fixed sequenceNumber failing in GetLogs.
Merge pull request #13 from pmantellini/master

Added customizable output format for Notifications and several bug-fixing. Added long argument format.