merged branch mist.
added minimig core UART input/output.
Paula updated with new UART module.
removed execute bit.
updated mist project.
updated mist top.
TG68K bus slowed down; change by AMR.
updated changelog.
new, more compatible handling of right mouse & second joystick buttons.
some changes to sdram controller.
added posedge / negedge 7MHz clock enables.
added posedge / negedge 7MHz clock enables.
temp fix.
ActionReplay using clock enables.