The old layout of `PointerRNA` was confusing for historic reasons:
```
typedef struct PointerRNA {
struct {
void *data;
} id;
struct StructRNA *type;
void *data;
} PointerRNA;
```
This patch updates it to:
```
typedef struct PointerRNA {
struct ID *owner_id;
struct StructRNA *type;
void *data;
} PointerRNA;
```
Throughout the code base `id.data` was replaced with `owner_id`.
Furthermore, many explicit pointer type casts were added which
were implicit before. Some type casts to `ID *` were removed.
Reviewers: brecht, campbellbarton
Differential Revision: https://developer.blender.org/D5558
This is the angular diameter as seen from earth, which is between 0.526° and
0.545° in reality. Sharing the size with other light types did not make much
sense and meant the unit was unclear.
Differential Revision: https://developer.blender.org/D4819
