Improve hiding options

[neerolyte]

I'm using Nagios so not sure if this makes any difference.

Currently I just have a button to "Hide acknowledged" but it would also useful to:

• Hide alerts for services that are in scheduled down time or on a host in scheduled down time
• Hide alerts for hosts that are in scheduled down time
• Hide alerts for services that have notifications disabled or on a host with notifications disabled
• Hide alerts for hosts that have notifications disabled
• Hide alerts that are "soft"

The Nagios Checker plugin for Firefox is able to do most of these I think - https://addons.mozilla.org/en-US/firefox/addon/nagios-checker/