Allow RenderStyles to be applied on Particles

[TheCamaleonMaligno]

While i was screwing around with A_SpawnParticle, i managed to make little beam effect but it looks a bit darker than it should be, then i wanted to set the particles' renderstyle to Add to make it a bit more shiny, but i couldn't, so...
As the title says. i'd like to request a feature that does such thing, perhaps by adding a new parameter for those functions that are asociated with the generation of particles, like A_RailAttack, A_CustomRailgun and A_SpawnParticle, or some flags like SPF_ADD, RGF_ADDTRANS. Is this possible?