Leaves `imgui.ini` in the current directory.

[shamefulCake1]

When running ospStudoi, it is creating a file called imgui.ini in it.

This is not really nice when no operations have been performed.

Please, consider using XDG_RUNTIME_DIR/.ospray_studio/imgui.ini

[BruceCherniak]

Thanks you for the issue. We will take it into consideration. For security reasons we have fairly restrictive policy on the creation of temporary files and where they may be placed.