Freeze Emulators

[LizardWiz]

Rick is concerned about arcade emulators, because they are based on MAME romsets. He wants to "freeze" an emulator, i.e.:

• Copy the emulator directory to a new directory name
• Change the "default" emulator to that directory name (if it is the default emulator, i.e. fbneo)

This will also ensure that the build does not break if they update the core through retropie setup.

[LizardWiz]

Daphne and Redream are currently owned by pi user, I think this is a mistake, but I will code the long way (copy as pi, change the directory ownership to whatever is in the zip file). I think probably this should be handled in check_root/process_iprovement, but it doesn't flip back to root for /opt/retropie/... (/opt/retropie/configs is always owned by pi).