rewrite keyboard handling
sdl: use new keyboard handling
gtk2: use new keyboard handling
modify -keymap help text
add -debug-ui option

Include flag for keyboard event debugging.
gtk2: add keyboard debugging
sdl: add keyboard debugging
macosx: add Dragon 200-E keyboard layout to menu
add -machine-keyboard option
New machine Dragon 200-E
expand -type to allow Dragon 200-E extended characters

A lot of these characters can't be typed on its keyboard, but work when
returned from INCH.
move sam HS/FS setting from vdg code to delegates

Delegates are already being called, so this is an easy abstraction.
add -invert-text option
Ctrl+Shift+H toggles Pause
docs: manual updates

 * Shorten Control to Ctrl
 * Ctrl+K behaviour changed
 * New shortcuts C+S+H, C+S+I
 * New options -debug-ui, -invert-text
 * Changed options -keymap
 * Shift+Return presses appropriate Caps Lock combo
docs: ChangeLog update
Shift+Space in translated mode pauses output

Also reinstate tilde mapping to that function.
tweak video ops - fix far left border in cross colour
fix coco 64K signalling

Only consider the output sink/source of connected pin, not the inputs.
fix inverted text on switching machines