many (many!) bugfixes, added fire FX back in (and improved it a lot) …

…added local renderbuffer for huge speed boost

-lots of bugfixes in Particle system
-added local rendering buffer (renders to buffer in heap)
-added fast and accurate color-add function
-bugfixes in render function
-added improved 'sticky' particles in collision (unfinished business)
-added ballpit animation back
-lots of tweaks to fire FX and fire rendering functions, looks even better now (still unfinished)
-added palette render option to fire

still many debug print outputs around, needs cleanup at one point