[PBUM] FPSC animation viewer script

This is just a script to help view animations and alt. textures in the game. Simply assign the anim_viewer.fpi script to the main AI of any dynamic entity and use PgUp/PgDn to cycle through animations and Home key to toggle textures, if assigned. Script can be useful for artists needing a way to easily check their work and for scripters deciding which animation to choose. Note: if using alttextures, be sure the textures are located in the texturebank and not the entity's directory.