Add support for three new variables:
 irssinotifier_ignored_nicks: A list of nicks to ignore higlights from
 irssinotifier_ignored_highlight_patterns: A list of regex patterns, will not
  higlight on any messages that match at least one.
 irssinotifier_required_highlight_patterns: A list of regex patterns, require a
  match on at least one of them before highlighting.
Replace some tabs with 4 spaces instead.
* Rename irssinotifier_required_highlight_patterns
  -> irssinotifier_required_public_highlight_patterns
* Change behaviour of above variable such that it will only require a match
  on public messages; PMs will all get through (unless blocked elsewhere).
irssinotifier.pl: move sending to its own thread

Even with the wget timeouts irssi will still block for a while
during network outages. Move sending logic inside its own thread
to avoid this.
irssinotifier.pl: add queuing to send_notification

Queue up to 10 notifications if sender thread is busy. Won't send
messages over 60 seconds old.
Merge pull request #122 from qvr/threaded

irssinotifier.pl: move sending to its own thread
Merge pull request #118 from turmoni/master

Add support for some more highlighting options (nick blacklist, pattern blacklist and "whitelist")