* 64 bit framebuffer for rt64
* Remove mention of motion blur cap from readme
* Add graphics.json option to control high precision framebuffers, disable clamping alpha for accumulation blur when using high precision FBs
* Increase dither noise strength at higher resolutions to make it more noticeable
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Co-authored-by: Mr-Wiseguy <mrwiseguyromhacking@gmail.com>