Use less memory for small features during tiling; Fix gridding of non-tile-aligned polygons

1.32.5

• Use less memory on lines and polygons that are too small for the tile
• Fix coordinate rounding problem that was causing --grid-low-zooms grids
  to be lost at low zooms if the original polygons were not aligned to
  tile boundaries

1.32.4

• Ignore leading zeroes when converting string attributes to feature IDs