Support for Quick Stats

[Subbeh]

I don't know if this is a feature I overlooked, but it would be great to be able to get the quick stats for all monitors, without having to call the API for each individual monitor.

Ideally something like get_quick_stats() which returns:

{
    "up": 71,
    "down": 0,
    "maintenance": 0,
    "unknown": 0,
    "pause": 2
}