Previously, it was kind of a mess. In different places it was using `char`, `short` and `int`. The changed properties are flags that are operated upon using bit operations. Therefore, the integer type should be unsigned. Since we only use 2 bits of these flags, `uint8_t` is large enough. Especially note the change I had to make in `RNA_define.h` to make this work. Reviewers: campbellbarton Differential Revision: https://developer.blender.org/D8844