kernal.s: flashes SSD1306 OLED display on VIA port A.
`make burn` has more permissive usbmodem glob.
kernal.s attempts to draw bitmap to SSD1306 OLED.

Currently appears to work correctly on emulator.
Should be changed from VIA port A to B to maybe work on hardware.
kernal.s: load ssd_mask_dc immediate, not absolute.

This was causing SSD1306 OLED D/C line to be held permanently low,
meaning data bytes were being interpreted as commands.
Replace adafruit bitmap data with simple full-screen pattern.

The adafruit data is displaying corrupted in emulator tests, while the
simple pattern displays correctly.
kernal.s writes full 128x32 OLED data, not just half.
kernal.s: VIA PCR sets both CB2 & CA2 to pulse output.
kernal.s has adafruit splash screen data again.
`make burn` verifies data.
README: 74HC00 in address decoder, disable RAM on low phase2 clock.
kernal.s uses ca65's cheap local @lables.

http://cc65.github.io/cc65/doc/ca65.html#ss6.5
kernal.s split into separate object source files.
SSD1306 moved to VIA port B.
memory.s: CopyPages; copy X pages from *$10 to *$12.
ssd1306 buffer in RAM, splash loaded from ROM.