CommonFilters - some new filters, and the future

Ok.

What to do about the code review of the cartoon shader patch? If I modularize CommonFilters at this point, by far the easiest and most error-free approach would be to include all changes into one monolithic patch - but that violates the general good-programming-practice guideline of “one commit, one feature”.

On the other hand, separating the modularization, cartoon shading improvements and these new filters into three separate patches would offer no real practical benefit. These changes are not orthogonal anyway, so separating them wouldn’t help even in the unlikely case that someone wants to backport only a subset of the new functionality into some old version.

What’s your opinion?