Limit runtime of stream rule matching, disable streams who excess it

Matching of stream rules is now limited in runtime with a configurable
timeout (default is 2000ms). If the runtime limit is exceed repeatedly
(with a configurable threshold and a default of 3), the stream is
disabled to protect the stability of the message processing pipeline.

Conflicts:
	graylog2-server/src/main/java/org/graylog2/Configuration.java
	graylog2-server/src/main/java/org/graylog2/buffers/processors/ProcessBufferProcessor.java
	graylog2-server/src/main/java/org/graylog2/notifications/Notification.java
	graylog2-server/src/main/java/org/graylog2/streams/StreamRouter.java