this solves 'Line filters not working if "Match similar lines" enabled - ID: 2796768 '
This patch splitts a diff in single parts, so after that we get diffs whitch contains only matching linefilters.
Also ignore empty line from diffutils is accepted as a linefilter condition.
So before a diff with more line, containing an empty line, or a line matching a linefilter was completly marked as diff.
Now also these signle lines will be marked as trivial.