Temp_downloads handling

[POE-Addon-Launcher]

Add a check that ensures the temp_download folder is an empty folder when setting it.

[Dissolator]

It's better to use temp_downloads path as parent for your app's temporary folder, which you can create, fill with files and delete without any risk to harm other users files. Also you can name it with timestamp to minimize risk of coincidence with already existing folders (like "pal"). Something like %temp_downloads%\pal2_05_06_2019\ should be enough

[POE-Addon-Launcher]

Yeah, that's also what I was thinking off, I was also thinking of when a user specifies a directory and it isn't empty I just create another folder inside of to use for PAL