Blender Git Loki

"Fix" for [#21591] Explode modifier bug
* The new default particle size is quite small, so exploded pieces didn't match the original pieces
* There's now an option to use the particle size (useful for some effects), but it isn't used by default
* This commit will change how some old files look (explode modifier and not 1.0 particle size), but the exact old behavior is achieved with the new "size" option