[Feature request] Paste files with Ctrl+V

[Test3lly]

Is your feature request related to a problem? Please describe.
Drag & drop can be bothersome sometimes and it's more difficult to automate with, say, AutoHotkey.

Describe the solution you'd like
Ability to paste files (Ctrl+V) that were copied in Explorer.

1. Select files in explorer.exe
2. Ctrl+C
3. Focus on the Waifu2x-Extension-GUI window.
4. Ctrl+V
5. The copied files are on the Waifu2x-Extension-GUI files list now.

Describe alternatives you've considered
Monitoring a directory for new, unprocessed files.

Additional context
Add any other context or screenshots about the feature request here.