Split stream reassembly in 2 parts: a part that sends ack'd data to the app
layer parsers as soon as it's available, and another part that queues up
data into larger chunks for raw inspection.
- improve locking of application layer handling, making sure that the flow cannot be freed/cleared when the detection engine is still working with it.
- add a check to the app layer detection to make sure that a match function will only inspect an app layer state if it's of the right type.