SVS 0.0.2 Release Notes

`pysvs` (Python)

Deprecated num_threads keyword argument from pysvs.VamanaBuildParameters and added num_threads keyword to pysvs.Vamana.build.
Exposed the prune_to parameter for pysvs.VamanaBuildParameters (see description below for an explanation of this change).
Added preliminary support for building pysvs.Flat and pysvs.Vamana directly from np.float16 arrays.

Removed nthreads member of VamanaBuildParameters and added the number of threads as an argument to svs::Vamana::build/svs::Vamana::build.
Added a prune_to argument to VamanaBuildParameters. This can be set to a value less than graph_max_degree (heuristically, setting this to be 4 less is a good trade-off between accuracy and speed). When pruning is performed, this parameter is used to determine the number of candidates to generate after pruning. Setting this less than graph_max_degree greatly reduces the time spent when managing backedges.
Improved pruning rules for Euclidean and InnerProduct. Vamana index construction should be faster and yield slightly improved indexes.
Added an experimental external-threading interface to svs::index::VamanaIndex.
Overhauled extension mechanisms using a tag_invoke style approach. This decouples the svs::index::VamanaIndex implementation from extensions like LVQ, reducing header dependence and improving precision of algorithm customization.

Enabled context-free saving and loading of simple data structures. This allows simple data structures to be saved and reloaded from TOML files without requiring access to the saving/loading directory. Classes implementing this saving and loading allow for more flexible storage.
Overhauled the implementation of saving and loading to enable more scalable implementation.
svs::data::SimpleData family of data structures are now directly saveable and loadable and no longer require proxy-classes.

Breaking Serialization Changes

Changed LVQ-style datasets from v0.0.1 to v0.0.2: Removed centroids from being stored with the ScaledBiasedCompressedDataset. Centroids are now stored in the higher level LVQ dataset.

Changes to library internals that do not necessarily affect the top level API but could affect performance or users relying on internal APIs.

Improved the performance of the LVQ inner-product implementation.
Moved dynamic uispatcher from the Python bindings into libsvs.
Data structure loading has been augmented with the svs::lib::Lazy class, allowing for arbitrary deferred work to be executed when loading data structures.
Removed the old "access mode" style API for multi-level datasets, instead using tag_invoke for customization.
Reduced binary footprint by removing std::function use for general multi-threaded functions.
Updated ANNException to use fmtlib style message directly rather than std::ostream style overloading. The new syntax turns
```
ANNEXCEPTION("Expected ", a, ", got ", b, "!");
```
to
```
ANNEXCEPTION("Expected {}, got {}!", a, b);
```

Added a benchmarking framework in /benchmark to automatically run and aggregate index construction and search for large scale benchmarks. Documentation is currently sparse but planned.