Make followed-by match behaviour configurable.

[t-moe]

Right now the followedBy operator will throw all matching objects into a queue. If the followedBy rule matches, the queue will be emptied completely (if possible). This might not always be the behavior that we want. We should add some more options (to the match function):

• first: only one element can be queued. all others will be discarded. This means that if the first matcher function matched on an object, it will not be presented with new objects until the followedBy rule matched.
• last: only the last queued element will be processed, the others will be discarded. This means that no matter how many objects match on the first matcher function, only the last object that matched will be presented to the followedBy matcher function
• combined: all queued elements will processed together. One object can match one multiple queued objects. This is the current behaviour.
• single: all objects will be queued, but a followedBy rule can only match on one queued object, per new incoming object.

[t-moe]

With 39f0d1bb0b4205c751db3cad92ce6fa275329277 I added the possibility to edit the queues manually.