databases/cego,devel/lfcbase: update 2.52.17 -> 2.52.18, 1.21.7 -> 1.21.8

lfcbase:
- BigDecimal::scaleTo: added RoundMode parameter which can either be
  UP ( round up )
  DOWN ( round down )
  HALFUP ( round up if neigbours equidistant or higher ) or
  HALFDOWN ( rond down if neighbors are equidistant or lower )

cego:
- Added support for lfcbase-1.21.8 ( BigDecimal::RoundMode ),
  Round mode ist setup in dbxml via database ROUNDMODE attribute
  ( either UP, DOWN, HALFUP, HALFDOWN )