All scene data collection is now done in a single sweep of frame
changing. Previous commits were already working towards this, and
but now it's done. Yay!
Over-all, switching to this approach gives huge speed boosts on
large scenes with animation, rigs, dependencies, etc. For such
scenes, frame changing is very expensive.
This eliminates writing temp files to disk for any part of the
Blender/Psychopath integration.
The option to export to a file still exists, however, by
specifying an export output path.
This was because it was taking the standard input from Psychopath,
but was buffering it and not reading it. The percentage complete
printouts would fill the buffer in some cases, and cause the
process to not exit since not all stdout had been handled.
