[C1][General][Patches] Implement monitor cleaning

[Tagunov Anthony <at...@nnt.ru>]

Hello, evrybody!

Looks like you've all been on holidays, guys, haven't you ;)

Please excuse my boldness, but let me propose the following mechanism for
Cocoon 1. This mechanism should solve a problem I can see no non-radical
way to solve: our monitors (in processors) generally never get cleaned.

One solution is to clean the monitor in the beginning of the process() method,
but what if the same processor (xslt, xinclude) get invoked twice (3 times..)
per request? For this solution we're likely to loose information about the request's
dependencies.

This is what I propose: let us implement some new interface (I called it
Invalidatable) and make the processors implement it (an alternative is
to add one method to Changeble interface).

Then whenever the page gets cleaned from cache (or when processing
traps) or when the page has been processed and the result has been
found to be !isCacheable()) we walk through the page's changebles
and if they implement the Invalidatable interface we call their method
to clean out their monitors for the given request. Your opinion?

Best regards, Tagunov Anthony
NNT Telecom Russia