v0.8.0

• Allow code in drop_features_where function.
• Add bounding box clipping to exterior boundaries transform to improve water boundary performance.
• Add kind normalisation functions for social facilities and medical features.
• Update road sort key value function.
• Add CSV spreadsheet property matching functions to provide sort_key value lookups for landuse, roads, and most other layers.
• Use more precision for json formatter on z16 and higher.