Fixes:
- The cheevos_print_xxx functions have moved to cheevos_format_value, will be better for RPS in the future.
- CHEEVOS_CONSOLE_ZX81_SPECTRUM -> CHEEVOS_CONSOLE_ZX81
- Remove all instances of CHEEVOS_ENABLE_LBOARDS
- cheevos_parse_format rewritten
New:
- Multiple values multiplied by nothing add correctly
- Failsafe to prevent LBs from submitting 0
- Memory patching for Atari 2600