log speedup: use only ui.write in changeset_printer.show - ui.status is not very useful, since this code is never executed when ui.quiet is true. - explicitly checking for ui.debug allows a regular hg log to run without looking at the manifest index - the calls to ui.note were converted for consistency

#!/bin/sh

hg init
touch a
hg add a
hg ci -m "a" -d "1000000 0"

echo 123 > b
hg add b
hg diff --nodates

hg diff --nodates -r tip

echo foo > a
hg diff --nodates