Bug in KisTopDownUpdateStrategy and adjustment layers

[Dmitry Kazakov]

Hi, all!

There is a bug in our merging mechanism. The strategy doesn't pay any
attention to the need rect of adjustment layers.
This causes border effects with some complex filters.

I've started fixing this, but it'll take a few days and it depends on
some refactoring of an update strategy.

I just wanted to notify you about this and ask not to change much
there for a few days =)

Testcase:
Create an adjustment layer (NOT a mask) with "blur" filter. Try to
draw something with a brush :)

-- 
Dmitry Kazakov