Fixes bugs and renames slice_len to slice_shape
Fixes bugs and renames slice_len to slice_shape

Renames utils.slice_len to utils.slice_shape

Addresses integer math corner-case resulting in inaccurate lengths in certain cases (i.e. slice(4,9,4) should have length 2)

Adds check to utils.slice_shape and utils.fix_slice to allow 'shape' to be an int

ooici/coverage-model,ooici/coverage-model