* [c_api] Update impl and interface for v1.5
- move IndexShards to dedicated module IndexShards_c.{h|cpp}
- remove getter/setters to unreachable fields
- reimplement faiss_IndexIVF_imbalance_factor (to use invlists)
- minor IndexIVF documentation tweaks
- Remove QueryResult, provide RangeQueryResult
* [c_api] Document FaissErrorCode
* [c_api] Update GPU impl and interface for v1.5
- Remove unavailable method setTempMemoryFraction
* [c_api] Relicense to MIT
In accordance to the rest of the project
Eduardo Pinho