ObjectBox C and C++ 4.0.2

• Made closing the store more robust; e.g. it waits for ongoing queries and transactions to finish
  (please still ensure to clean up properly on your side, this is an additional safety net)
• Made Box API more robust when racing against store closing
• Improved C++ APIs for nearest neighbor search (query building etc.)
• Some minor HNSW performance improvements
• Add "vectorsearch-cities" example

Sync

• Fixed a serious regression; please update to the latest version asap!
• Added a special compression for tiny transactions
• Embedded clusters (note: the cluster feature may not come with all editions of the library)
• Add FlatBuffers based configuration for Sync Server