increased threshold for line merging in TextChunk.group_by_lines
remove debugger
new group_by_lines
Merge remote-tracking branch 'origin/extraction-modifications-and-refactor' into extraction-modifications-and-refactor
dont include space-only textchunks in column_positions init
take empty textchunks into account when calculating columns
adjust heuristic's arbitrary constant to make tests pass
closes #68
Merge branch 'master' into icdar-groundtruth-tests