Extending semantics of absPath Parameter of ObservationManager.addEventListener

[Michael Dürig]

Hi,
Since JCR observation only supports listening on a single path per 
listener, a commonly seen pattern is listeners registered on the root 
path and then filtering for the required paths in the event handler. 
This causes a lot of overhead in the case where the number of events on 
the target paths is low wrt. the total number of events.

One way we could address this in an backward compatible way is to 
slightly extend the semantics of the absPath parameter and allow for a 
list of path instead of a single one. AFICS we could use | for 
separating such paths (e.g. /foo/bar|/baz/qox). This could then also be 
back ported to JR2 if needed. WDYT?

Michael