maprequest() now preconfigures new windows...

... which results in heavily reduced flickering!
However there are lots of warning messages appearing upon start (mostly
because stwm finds windows from the previous session, God knows why).
Make stuff work and halfway properly.

... although doing things properly gets back the slight flickering when
creating a new terminal window. *sigh*

There are warning messages at the beginning, don't know what causes
them, can't remember having seen them before, need to check what's the
difference between 'master' and 'request'.