Release/unlock tools for generating PSF files

[Arhowk]

PSF files are necessary for getting specific shapes, curvatures, and paths in particles and are used constantly in particle design (most notably in cosmetics- psf's are always used to align a particle to the edge of a sword or bow or anything). Custom games don't have any tools available to create these files which hurts when we need to use them, so it would be nice for us to be able to create psf files.

[robincodex]

The PSF file is create in the model editor: Model -> Add Particle Snapshot.
By default it will auto create psf to game\dota_addons\xxx\particles\models