Loader does not inform other loaders of updates

[spillerrec]

Files are loaded into a static cache, as other widgets most likely will need the same files. However if one loader attempts to load a file the other loader is currently loading, it will think it is already done loading.

This way the loader might think it is finished loading before the other loaders are done loading files it depends on. This would cause parts not to appear in the converted mesh, as it is done immediately after the loader finishes.