Note in pixel shift register

Upgraded to kicad 7

Video memory bus and connections to Z80

Added address signals from Z80 to video memory

Some steps in bank switching and crtc circuits - crtc pixel clock generator - 2k ram, enabling logic (heavily incomplete) - other 2k ram, annotation regarding data bus

Recovered IO component numbering lost in old commit

Add test point.

28L22 confirmed glue logic. Address selection mux trio. Pixel clock.

Video generation: video memory, character ROM and dot pattern generation.

Moved keyboard circuit in its sheet