v1.6.0

• New features:
  • Add support for 2x2 metatiles (and 512px tiles). See #163, #166, and #169.
  • Cut child 256px tiles from 512px parent in the 2x2 metatile, rather than re-requesting that 256px bbox from database. See #158.
  • Pass nominal zoom instead of coordinates. See #161.
• Enhancements:
  • Drop parts of MultiPolygons which lie outside the clip boundary of the tile (primarily affects buildings and water layers). See #171.
  • Make queue sizes configurable, and default to smaller queue size to accomodate larger 2x2 metatiles. See #172.
  • Move existing tiles of interest (TOI) instead of copying it to avoid AWS Redis failover. See #122.
  • Load new TOI from file 'toi.txt', just as the TOI dump process saves to 'toi.txt'. See #122.
• Bug fixes:
  • Delete rejected jobs from SQS queue. See #173.
  • Trap MemoryError and let ops recover process. See #174.
  • Fix LinearRing error. See #175.