Added HK heads as an option for Sparks.

• Original Bioware textures upscaled
  
• Normal maps for 47 and 51 fixed to remove shading errors on calves and wrists
  
• Leg models tweaked to prevent shading errors on the tops of the thighs
  
• Emissive masks recreated for cleaner lights
  
• New PBR masks created, including new from-scratch albedo for 51
  
• Materials corrected to properly generate metallics