Better centering in NTSC

• Fix system variable injection
• Add hotkeys
• Send tape motor control to UART_TX

• TAP file and real tape input support
• Sound generator rewrite and fixes (thanks to Nino Porcino)

Common build for PAL and NTSC

Bigger OSD

Casette button sense input change - fix Tuthankam controls

• Separate NTSC build.
• Change in the ROM format!

Several fixes for keyboard, 1541, VIC chip

• CRT support with auto-reset
• YPbPr support (thank Till)
• sticky joystick right direction fix

New VIC20 core