Now EFL# doc is generated by the followings.
Internally generated classes exist in EFL# doc.
(e.g. Class ImageProgress_StructConversion, Class BoxNativeInherit, etc.)
I think that these internally generated classes should be removed from EFL# doc.
After the DotNet Core support, there still remain the following issues:
- `*_StructConversion` classes: Do they need to be public?
- ~~`*Concrete` classes.~~
- ~~`*NativeInherit` classes~~.
- `On_*Evt` methods: Do they need to be public?
- ~~`register_event_proxies` method~~
- `static_cast` method: Does it need to be public?
- ~~`klass` field~~
- ~~`nativeInherit` field~~
- `NativeClass` property: Does it need to be public?