Renderer wishlist/buglist

[katajakasa]

Just a big lump of stuff for now

TODO:

• Make the shaders use remappings to get correct shadows and stuff GL remapping/blending stuff #633
• Drop unnecessary creation of intermediate sprites -- just pass the orinal RLE coded one to renderer, and let renderer decide on what to do. Do hit collision stencils (bit-packed), for sprites /that require them/.
• Figure out the video renderer API -- we need an easy way to add new renderers.
• Text shadows are broken, fix them
• Intro rendering is broken, fix it
• HAR transparency (bf tags) is broken, fix it
• HAR shadows are broken, fix them (under har shadow)
• HAR shadow trails are broken, fix them (jaguar leap)
• Pyros palette tricks (fire) are broken, fix them
• Credits transparency is broken, fix it
• Menu text (blue grid) background transparency is broken, fix it
• Make the texture atlas do deletions on unused textures (GC with LRU when full?), and stop clearing it between scenes.
• Palettes should be built in tick functions, and then be complete when fed to the renderer. Also, add dirtiness flag and damage information.