v1.2.2 dev release

*** Hotfix update to fix EDSK save issue in v1.2.1. ***

Changes since the last release:

• fixed missing video update before display memory changes.
• fixed CPU emulation of undocumented BIT instructions (#56)
• fixed media warnings for unattached devices (#24)
• fixed unwanted ROM symbols in user code (#26)
• fixed ATA device revision string not showing date correctly.
• fixed menu issues, usually seen as duplicate entries [Win32].
• fixed disassembly of some DDCB undocumented instructions.
• restored full double register display in instruction trace (#55).
• added samdos2 symbols to debugger (#44)
• added address symbols to trace view (#43)
• added proper version number to About (#45)
• added hidden option to simulate disk read errors, for developers.
• added SAMdiskHelper version check to recommend upgrade [Win32].
• improved dosboot to only trigger in ROM1.
• increased menu MRU from 6 to 9 items [Win32].