Import from current fails if custom order is enabled

[Pixelz]

"Import from current" fails if you try to import a set of mods previously launched with "Use custom order" enabled. The mod manager looks for files with "pmm_" prefix and can't find any.

[ThibautSF]

It's not really a bug, it's a result due to the fact that pmm_ files are temp files.

First, I need to solve #5 and thus try to enhance that.