Importing and exporting of single code files

[FeniXb3]

Feature request from TinkerSmith:

Regarding what I just posted on the edu channel, what are the chances that code snippets can be dragged into the code editor? Kinda the same way sprites are added (drag&drop). I imagine to keep a library of snippets, extension *.ms for sure, that can be used as needed. 'helpers.ms', 'verctorstuff.ms', you get the idea.

Yes, I can do that manually with the export/import now, but drag/drop style (or load button) would probably be easier for starters. https://discord.com/channels/593735633130749972/667401412405362688/870822111755763712

This should be quite easy to add. I think it's worth to make it possible to import file by both drag & drop and from a button to make it also accessible for mobile users.