4.2.1

This was a bug-fix only release.

• Core-fetch failsafe now fetches a pinned version (Thanks to @gantoine)
• Fixes video rotation on the arcade core (Thanks to @allancoding)
• Updated French af-FR translation (Thanks to @t3chnob0y)
• Fixes switching between cores.
• Change: Localstorage settings are now stored by game instead of by system.
• Fixed gamepad input for c-down.
• Fixed RetroArch always assuming save is .srm.
• Fixed EJS exit event
• Hide the "save/load save files" buttons if unsupported.
• Corrects the order of the core list.
• Corrects behaviour of the placement of bios/parent/patch files.
• Fixed rar decompression.
• Fixed picodrive core (sega32x)
• Fixed libretro-uae core (amiga)