Fix crashing bug when layers are being merged with -l

• Fix crashing bug when layers are being merged with -l

Add an option to do line simplification only at zooms below maxzoom

• Add an option to do line simplification only at zooms below maxzoom

More parallelization and better tile boundary alignment

• Make sure line simplification matches on opposite sides of a tile boundary
• Use multiple threads for line simplification and polygon cleaning
• Add option of parallelized input when reading from a line-delimited file

Fix internal error when number of CPUs is not a power of 2

• Fix internal error when number of CPUs is not a power of 2
• Add missing #include

Distinguish base zoom from max zoom

• Base zoom for dot-dropping can be specified independently of
  maxzoom for tiling.
• Tippecanoe can calculate a base zoom and drop rate for you.

Encode numeric attributes as integers instead of floating point if possible

• Encode numeric attributes as integers instead of floating point if possible

Better handing for features crossing the antimeridian, and some bug fixes

• Features that cross the antimeridian are split into two parts instead
  of being partially lost off the edge
• Bug fix for problem that would occasionally produce empty point geometries
• More bug fixes for polygon generation

Layer merging, better polygons, more utilities, better CPU utilization

• More polygon correctness
• Query the system for the number of available CPUs instead of guessing
• Merge input files into one layer if a layer name is specified
• Document and install tippecanoe-enumerate and tippecanoe-decode

Multithreading, better polygons, smaller memory footprint, and other improvements

• Tile generation is multithreaded to take advantage of multiple CPUs
• More compact data representation reduces memory usage and improves speed
• Polygon clipping uses Clipper
  and makes sure interior and exterior rings are distinguished by winding order
• Individual GeoJSON features can specify their own minzoom and maxzoom
• New tile-join utility can add new properties from a CSV file to an existing tileset
• Feature coalescing, line-reversing, and reordering by attribute are now options, not defaults
• Output of decode utility is now in GeoJSON format
• Tile generation with a minzoom spends less time on unused lower zoom levels
• Bare geometries without a Feature wrapper are accepted
• Default tile resolution is 4096 units at all zooms since renderers assume it

Multithreading, better polygons, smaller memory footprint, and other improvements

• Tile generation is multithreaded to take advantage of multiple CPUs
• More compact data representation reduces memory usage and improves speed
• Polygon clipping uses Clipper
  and makes sure interior and exterior rings are distinguished by winding order
• Individual GeoJSON features can specify their own minzoom and maxzoom
• New tile-join utility can add new properties from a CSV file to an existing tileset
• Feature coalescing, line-reversing, and reordering by attribute are now options, not defaults
• Output of decode utility is now in GeoJSON format
• Tile generation with a minzoom spends less time on unused lower zoom levels
• Bare geometries without a Feature wrapper are accepted
• Default tile resolution is 4096 units at all zooms since renderers assume it