- reengineering of breakable stones:
- renaming:
st-stone_break -> st_break_oxydc
st-break_gray -> st_break_plain
st-break_bolder -> st_break_boulder
st-break_acblack -> st_break_black
st-break_acwhite -> st_break_white
st-bug -> st_break_bug
st-laserbreak -> st_break_laser
- all these stones are now one class, st_break is st_break_plain