Code review comment for lp://qastaging/~benoit.pierre/bzrtools/colordiff_when_tty

OK, done, cdiff can now take a --color option:

  --color=ARG Color mode to use. "auto": Only colorize output if
                                  terminal supports it and STDOUT is a TTY. "never":
                                  Never colorize output. "always": Always colorize
                                  ouput (default).

I tested it on Linux and Windows (in a regular command prompt and with a cygwin shell).