- ubb-vga.c (mode_db): added new mode "640x480/61"
- ubb-vga.c (setup, line): MSC_CLKRT is reset when the MSC resets. Moved
it from "setup" to "line".
- ubb-vga.c (clkrt, setup, line): pick the highest available MSC clock
and adjust the bus clock divider accordingly
- ubb-vga.c (main): added commented-out clock debugging output
- README: added XEN-1510T result for "640x480/61"
- README: added compatibility of double mode
- ubb-vga.c (usage, main): new option -d to double the number of set/clear
pairs (making lines longer and the apparent pixel clock slower)
- ubb-vga.c (grab, session, main): have a complete set/clear pair for each
pixel in double mode