- When returning the number of items in a collection use BLI_*_len()
- Keep _size() for size in bytes.
- Keep _count() for data structures that don't store length
(hint this isn't a simple getter).
See P611 to apply instead of manually resolving conflicts.
The single byte version of hash_data was casting from unsigned char
instead of signed.
This didn't cause any errors since the result of each aren't compared.
Even so, better keep them matching.
Two were actual bugs, though they existed only in unused code:
* In Freestyle it was unintentionally copying a scene rather than referencing it.
* In BLI_array_store_is_valid there was use of uninitialized memory.
