igl | shell | ImageLoader : make fileLoader() function become public. #1916

Job	Run time
Android (Ubuntu)	9m 37s
cmake-build (Windows - MSVC 2022, windows-latest, Debug, cl, cl, Visual Studio 17 2022, -DIGL_WIT...	7m 37s
cmake-build (Windows - MSVC 2022 (no OpenGL), windows-latest, Debug, cl, cl, Visual Studio 17 202...	6m 25s
cmake-build (Ubuntu - Clang, ubuntu-latest, Debug, clang, clang++, Unix Makefiles, -DIGL_WITH_TRA...	7m 12s
cmake-build (Ubuntu - GCC, ubuntu-latest, Debug, gcc, g++, Unix Makefiles, -DIGL_WITH_TRACY=ON -D...	5m 14s
cmake-build (macOS - Clang (Xcode), macos-latest, Debug, clang, clang++, Xcode, -DIGL_WITH_VULKAN...	36m 7s
cmake-build (macOS - Clang (Unix Makefiles), macos-latest, Debug, clang, clang++, Unix Makefiles,...	58m 13s
	2h 10m 25s

Provide feedback