Develo system reports that unused bits in palette entries are high, not low

[dshadoff]

Need to validate whether palette entries' unused bits are: a) low, as mednafen shows b) high, as develo seems to indeicate, or c) actually retained but unused

While editing of data may be easier if the unused bits are represented as zeroes, Mednafen should reproduce whatever is on real hardware for any programmatic reads (if it doesn't already do so ).

[dshadoff]

I created a test program to check this; regardless of the memory editor view of the palette values, from the machine's point of view, the unused bits are all high. PCE_test_VCE.zip