[Interfaces] Moved IANEmitter to interfaces/an/.
[Interfaces] Added AN::NotifyFlag{,s}.

For #1313 and #1331.
[AN] Fixed code style somewhat.
[AN] NotificationRule::AddMethod().

Refs #1313 and refs #1331.
[AN] RulesManager::HandleEntity() for #1331.
[AN] Handle "x-leechcraft/notification-rule-create" for #1331.
[Util] Added MakeANRule helper for #1331.
[AN] NotificationRule::AddFieldMatch().
[Overall] Put all QFlags operators in global scope.
[Interfaces] Added AN{Int,String,}FieldValue for #1331.
[AN] Style fixes.
[Util] Migrate MakeANRule to ANFieldValue for #1331.
[AN] Migrate matcher to AN{String,Int}FieldValue internally.

All for #1331.
[AN] SetValue() for typed matchers for #1331.
[AN] Handle custom fields in entity-based rules.

This finally closes #1331.
[Azoth] Core::GetPluginProxy().
[Azoth] Fix SourceID AN field description.
[Azoth] Actions for registering state change/online in AN.

Closes #1313.