fix typo

* [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

Bugfixes:
- slow scanning of inverted lists (#836).

Features:
- add basic support for 6 new metrics in CPU `IndexFlat` and `IndexHNSW` (#848);
- add support for `IndexIDMap`/`IndexIDMap2` with binary indexes (#780).

Misc:
- throw python exception for OOM (#758);
- make `DistanceComputer` available for all random access indexes;
- gradually moving from `long` to `int64_t` for portability.

* [c_api] use all relevant flags in compilation

* [c_api] Remove redundant IndexIVFFlat declarations

- From IndexIVF_c.h, already declared in IndexIVFFlat_c.h

* [c_api] type changes

- replace `long` with a more suitable type
- provide definitions for `faiss_component_t` and `faiss_distance_t`

* [c_api] Define CFLAGS and CUDACFLAGS