Changes

• Fix covers in JPEG format not loading on windows since v0.7.3
• Fix RMG not inhibiting the screensaver during emulation
• Fix not having supported archives listed when opening 64DD Disks through 'Open Combo'
• Fix RMG-Audio spamming the log with sample warnings
• Add captions to all file and directory dialogs
• Improve logging when retrieving OpenGL context fails