Fix panic in table parser

[Andrew-Morozko]

Code in func (b *tableParagraphTransformer) parseRow used the segment's Value to calculate some offsets as if Value always corresponds 1 to 1 to the source. Segments with padding cause incorrect behavior generally, and an out-of-bounds source access in pathological cases.

I switched the code to use padding-aware segment.TrimLeftSpace and segment.TrimRightSpace instead of raw util.TrimLeftSpaceLength and util.TrimRightSpaceLength