v0.9.3

• 04fd1bf: Added GeoJsonPagination
• fe47d86: Improved ValidationError message of GeometryField
• a3ddd3d: Improved serialization performance between 25% and 29%
• fb6ed36: GeoModelSerializer deprecated because obsolete
• #66: geometry now allows None values according to the GeoJSON spec
• #67: discern False or empty string values from None in GeoFeatureModelSerializer