tests/test-rebuildstate.out

color: colorize based on output labels instead of parsing output

By overriding ui.write(), ui.write_err(), ui.popbuffer(), and ui.label(),
the color extension can avoid parsing command output and simply colorize
output based on labels.

As before, the color extension provides a list of default colors for
core commands/labels. Other extensions can provide their own defaults by
specifying a colortable dict (similar to cmdtable).

In this process, --color is promoted to a global option and the deprecated
--no-color option is removed.

adding bar
adding foo
% state dump after
n 666         -1 bar
n 666         -1 foo
% status
! bar
? baz
C foo