Show "pseudo" in unknown class error

I propose to display "$pseudo", passed to "kApplication::recallObject" method, when class, associated with given pseudo is not found. This useful, since when class is not found, then "empty string" is displayed instead of it's name (in several cases) and such error message won't help to detect problem source.

Also "kApplication::printTrace" added to allow method call trace printing, when debug mode is not available.