- Removed explicit PCH.
- Fixed includes to compile for all supported engine versions, including non-unity builds.
- Configured build.cs to treat ImGui as an engine module and added stricter compilation rules.
- Added ImGuiTextureHandle that is implicitly convertible to ImTextureID and can be used directly with ImGui interface.
- Added to ImGui Module interface allowing to register, update and release textures or find handles to existing resources.
- Refactored Texture Manager and added functions allowing create, update or release resources for user textures.
- Loosened resource verification policy in Texture Manager to work smoothly with external requests and to handle gracefully situations when invalid texture id is passed to ImGui.
- Introduced ‘error texture’ that is used for invalid resources.
