Some arguments against the change:

• The underlying Lucene API just refers to 'spatial'
• We are changing/breaking an existing API (it is still experimental, so I guess we can do it)

Also how far do we go with the rename? There is obviously `@Spatial`, but also `SpatialMode`, `SpatialBridgeProvider`, `EntityDescriptor#addSpatial|getSpatials`, `IndexedMapping#spatial`, `SpatialContext`, `SpatialMatchingContext`. `SpatialFieldBridge` and sub classes, etc. Also there is the question about the package names itself, for example `org.hibernate.search.spatial`. If we rename we should do it consistently, right? Package names probably could stay, but the mentioned classes and methods should probably be renamed. Not sure whether it is worth the effort.