* Started graphics refactoring
* myb3k.cpp: refactored graphics circuit and added color in 320x200 mode
* myb3k.cpp: fixed speed issue by reducing CPU clock by 50% as suggested by RAM waitstates in the schematics where the CRTC uses the other 50%
* myb3k: fixed text scrolling
* myb3k: -ramsize now supported with 128K option and 256K default
* myb3k: 80 character mode added, eg 640x200
* Emulate the INT7 pull down and up for the keyboard. Initial support for JB3000 keyboard.
* myb3k: Added hi-res 640x400 mode and crude cursor support for 40 character mode
* Keyboard improvements using BACKSLASH2 keycode.
* myb3k_fdc.cpp: addressed review comment
* myb3k.cpp: Added initial monochrome monitor support
* myb3k.cpp: Adjusted the monochrome color palette to match the 525Nm of P39 phoshor in the Ericsson DU4721 monochrome monitor
* myb3k.cpp: added printer support and completed interupt support including jumper settings
* myb3k.cpp: Added softlist for Ericsson step/one
* myb3k.cpp: cleanup and srcclean:ed
* myb3k.cpp: Fixed crude support for 36x25 color text mode
* Fixed build
* myb3k_fdc.cpp: fixed review comment
* mybr3k: fixed DOS 2.11 boot in 256KB mode
* myb3k.cpp: Added graphics mode 0 which have the peculiar characteristic of different resolutions depending on the monitor used (2 connectors)
* myb3k: Separated keyboards into separate device implementations.
* myb3k: addressed review comments
