All these changes will allow us to more easily add Lol Engine as a
submodule of another Git project.

Not all programs support this feature for now, but that’s because they
don’t support the scene framework either, and will need patching. Also
the default postprocess is deliberately exaggerated for now.

Merge threadbase.h into thread.h since we no longer need to have “secret”
thread implementations; all the platforms we care about have std::thread
or just don’t support threads at all.

Added Texture (by image) update in TextureImage (and tileset)
Added lolimgui first integration pass

Added InputProfile in Controller
Added ExecLuaCode

Big FAT pass on windows-warning. It is better now.

support for enable_if and other template metaprogramming techniques),
for Clang (related to static const template class member initialisation)
and for GCC (related to forward declaration of non-int enum classes).

for the next implementation of large float numbers.

can reuse it for other noise implementations.

wanted convolution or dithering kernels.