refactoring: make Freebloks3DView.MyRenderer a static class
refactoring: extract class FreebloksRenderer to separate file
refactoring: rename attribute CSpielClient spiel to client
refactoring: reorganize package and subpackages of .view
refactoring: split AbsEffect classes into separate files
refactoring: remove dead code; move stone immediately when starting dragging

fixes graphical glitch with stone appearing somewhere else when starting to drag
server: only use 2 threads

possibly increases responsiveness and speed, because of less overhead on 2 cores

who knows...
refactoring: fix weird coordinate transformations in previous code

the top left corner (yellow starting point) has the board coordinates 0/0
the blue start corner has 0/19

in unified coordinates, the bottom left corner has 0/0
game: add effect before committing stone. fixes glitch where stone was displayed shortly before effect