[BUG] in sbu conversion, prediction- and color- calculate patches differently

[kaczmarj]

in email...

Patch locations in prediction-* files are computed using the following coordinate computations:

(df.minx + (df.width / 2)).round().astype(int)
(df.miny + (df.height / 2)).round().astype(int)

Patch locations in color-* files were being computed as follows:

df.minx + ((df.minx + df.width) / 2)
df.miny + ((df.miny + df.height) / 2)

The coordinate computations are different leading to mismatch between patches in color-* and those in prediction-*.